Magnetic recording head, method for manufacturing the same, magnetic recording device, and method for manufacturing magnetic recording medium

Abstract

The present invention provides a magnetic recording head having a magnetic film including a write gap in which a recording surface side gap width is narrower than a back surface side gap width and an opening portion formed by ion beam processing is provided at a gap end portion on the recording surface side of the write gap, a magnetic recording apparatus including the magnetic recording head, a manufacturing method of the magnetic recording head, and a manufacturing method of a magnetic recording medium having a servo pattern including forming the servo pattern on the magnetic recording medium by the magnetic recording head.

Description

Technical Field

[0001] This invention relates to a magnetic recording head and its manufacturing method, a magnetic recording device, and a method for manufacturing a magnetic recording medium. Background Technology

[0002] Information can be magnetically recorded on a magnetic recording medium by forming a magnetized region on the magnetic layer of the magnetic recording medium using a magnetic recording head. A servo signal is an example of such information. The magnetized region formed to obtain the servo signal is also called a servo pattern. Patent Document 1 discloses a magnetic recording head for forming a servo pattern.

[0003] Previous technical documents

[0004] Patent documents

[0005] Patent Document 1: US Patent No. 6269533 Summary of the Invention

[0006] The technical problem to be solved by the invention

[0007] Patent Document 1 discloses a method for forming a gap with a shape corresponding to the shape of a servo pattern to be formed on a magnetic recording medium using a focused ion beam (claim 1 of Patent Document 1, etc.). In column 3, lines 62-67 of Patent Document 1, it is described that a focused ion beam can form an extremely precise gap, etc.

[0008] Therefore, the inventors investigated forming gaps through ion beam processing during the manufacturing process of magnetic recording heads. In this study, the inventors believed it desirable to improve the recording capability of magnetic recording heads with gaps formed through ion beam processing. This is based on the following reasons: High-coercivity magnetic recording media exhibit excellent information retention due to their superior thermal stability, but they also tend to be difficult to record. Therefore, in order to record on high-coercivity magnetic recording media, a magnetic recording head with high recording capability is required. Thus, in order to record well even on high-coercivity magnetic recording media, a high recording capability of the magnetic recording head is desirable.

[0009] One aspect of the present invention aims to provide a magnetic recording head having a gap formed by ion beam processing and capable of high recording capability.

[0010] means for solving technical problems

[0011] One aspect of the present invention relates to a magnetic recording head.

[0012] It has a magnetic film including a write gap.

[0013] In the aforementioned write gap, the width of the gap on the recording surface is narrower than the width of the gap on the back surface, and

[0014] The end of the gap on the recording surface side of the aforementioned writing gap has an opening formed by ion beam processing.

[0015] In one embodiment, the magnetic recording head described above can be a servo write head.

[0016] In one embodiment, the width of the recording surface side gap of the aforementioned writing gap can be greater than 0.2 μm and less than 1.5 μm.

[0017] In one embodiment, the back side gap width of the aforementioned writing gap can be greater than 2.0 μm and less than 20.0 μm.

[0018] In one embodiment, the thickness of the magnetic film can be greater than 1.0 μm and less than 10.0 μm.

[0019] In one embodiment, the aforementioned writing gap may include a non-magnetic material portion at the gap end on the back side.

[0020] In one embodiment, the thickness of the non-magnetic material portion can be 5% or more and 90% or less relative to the thickness of the magnetic film.

[0021] In one embodiment, the nonmagnetic material constituting the aforementioned nonmagnetic material portion may be silicon oxide.

[0022] In one embodiment, the aforementioned magnetic film can be an iron nitride alloy film.

[0023] In one approach, the aforementioned ion beam processing can be focused ion beam processing.

[0024] One aspect of the present invention relates to a magnetic recording apparatus including the aforementioned magnetic recording head.

[0025] In one embodiment, the magnetic recording device described above can be a servo writer.

[0026] One aspect of the present invention is a method for manufacturing the above-mentioned magnetic recording head, comprising:

[0027] A non-magnetic material portion is formed on the substrate;

[0028] A magnetic film is formed on the substrate to cover the non-magnetic material portion; and

[0029] In the portion of the magnetic film where the writing gap should be formed, an opening is formed by ion beam processing.

[0030] The portion processed by the ion beam has a non-magnetic material portion between the magnetic film and the substrate.

[0031] In one approach, the aforementioned ion beam processing can be focused ion beam processing.

[0032] One aspect of the present invention relates to a method for manufacturing a magnetic recording medium having a servo pattern, comprising forming a servo pattern on the magnetic recording medium using the aforementioned magnetic recording head.

[0033] In one approach, the aforementioned servo pattern can be a timing-based servo pattern.

[0034] In one embodiment, the vertical coercivity of the aforementioned magnetic recording medium can be above 2800 Oe.

[0035] Invention Effects

[0036] According to one aspect of the present invention, it is possible to provide a magnetic recording head having a gap formed by ion beam processing and capable of high recording capability, a magnetic recording apparatus including the magnetic recording head, and a method for manufacturing the magnetic recording head. Furthermore, according to one aspect of the present invention, it is possible to provide a method for manufacturing a magnetic recording medium including forming a servo pattern on a magnetic recording medium using the aforementioned magnetic recording head. Attached Figure Description

[0037] Figure 1 This shows an example of the configuration of the data tape and servo tape in a magnetic tape.

[0038] Figure 2 This represents a servo pattern configuration example for an LTO (Linear Tape-Open) Ultrium format magnetic tape.

[0039] Figure 3 This is an explanatory diagram of the azimuth angle α.

[0040] Figure 4 This is an explanatory diagram of the azimuth angle α.

[0041] Figure 5 This represents a configuration example of the write gaps in the magnetic recording head.

[0042] Figure 6A This is an explanatory diagram showing the location for measuring the gap width.

[0043] Figure 6B This is an explanatory diagram showing the location for measuring the gap width.

[0044] Figure 7 This is a perspective view showing an example of the aforementioned magnetic recording head.

[0045] Figure 8 yes Figure 7The cross-sectional view of the magnetic recording head 20 shown.

[0046] Figure 9 yes Figure 8 A partially enlarged cross-sectional view of the magnetic recording head 20 shown.

[0047] Figure 10A This is an enlarged view (cross-sectional view) of the portion of the magnetic film with the writing gap.

[0048] Figure 10B This is an enlarged view (cross-sectional view) of the portion of the magnetic film with the writing gap.

[0049] Figure 11 express Figure 10A An explanatory diagram illustrating the method for forming the writing gap.

[0050] Figure 12 This is a schematic diagram showing the structure of the servo writer. Detailed Implementation

[0051] [Magnetic recording head]

[0052] One aspect of the present invention relates to a magnetic recording head having a magnetic film including a writing gap, wherein the width of the writing gap on the recording surface side is narrower than the width of the writing gap on the back side side, and the end of the writing gap on the recording surface side has an opening formed by ion beam processing.

[0053] In this invention and specification, the "write gap" included in the magnetic film of the magnetic recording head refers to a magnetic interval, and specifically, an interval that generates a leakage magnetic field for recording. The width of this magnetic interval is the gap width. The magnetic interval includes a physical interval, i.e., an opening, and portions that are not physically separated but are magnetically separated due to the presence of non-magnetic material. As described in detail below, the aforementioned magnetic recording head includes a write gap with an opening formed by ion beam processing at the gap end on the recording surface side.

[0054] In this invention and specification, "recording surface side" refers to the surface side of the magnetic recording head that is in contact or non-contact with the magnetic layer surface of the magnetic recording medium being recorded during recording. The surface side opposite to this surface is called the "back side". "Magnetic layer surface" is synonymous with the magnetic layer side surface of the magnetic recording medium.

[0055] In this invention and specification, "recording surface side gap width" refers to the gap width at the recording surface end of the write gap, and "back side gap width" refers to the gap width at the back side end of the write gap. A magnetic recording head typically has multiple write gaps. In the aforementioned magnetic recording head, at least one write gap has a recording surface side gap width narrower than the back side gap width and has an opening formed by ion beam processing at the gap end on the recording surface side. Preferably, all write gaps have a recording surface side gap width narrower than the back side gap width and have an opening formed by ion beam processing at the gap end on the recording surface side. Hereinafter, a "write gap with a recording surface side gap width narrower than the back side gap width and an opening formed by ion beam processing at the gap end on the recording surface side" will be referred to as a "narrow-width recording surface side write gap." In this invention and specification, "recording surface side gap end" refers to the end portion of the recording surface end of the write gap. "Back side gap end" refers to the end portion of the back side end of the write gap. The determination that the width of the write gap on the recording face side is narrower than that on the back side is based on the following measurements. The gap width was measured at three locations on both the recording face side and the back side. Details of the gap width measurement are described later. For both the recording face side and the back side, the arithmetic mean of the measured values ​​was used to determine the width of the write gap on both the recording face side and the back side.

[0056] Furthermore, the "recording surface side gap width of the write gap" in the magnetic recording head, which is the object of the measurement, is calculated as an arithmetic mean obtained by measuring the recording surface side gap width at three locations within a single write gap for all the narrow recording surface gaps of the magnetic recording head. Similarly, the "back side gap width of the write gap" in the magnetic recording head, which is the object of the measurement, is calculated as an arithmetic mean obtained by measuring the back side gap width at three locations within a single write gap for all the narrow recording surface gaps of the magnetic recording head.

[0057] The measurement sites for the gap width in each writing gap are set at three locations: near the center of the writing gap, near one end (e.g., approximately 10 μm from the end), and near the other end (e.g., approximately 10 μm from the end). The gap width can be measured using a known measuring device with length measurement capabilities, such as a laser microscope or a scanning electron microscope (SEM). Measurements can be performed using either non-destructive or destructive methods. For example, the recording surface-side gap width can be measured non-destructively by observing the magnetic recording head from the recording surface side. However, destructive methods can also be used to measure the recording surface-side gap width. On the other hand, the back-side gap width can usually be measured using destructive methods. For example, a cross-sectional specimen including the writing gap portion can be prepared at the gap width measurement site, and the back-side gap width can be measured on this cross-sectional specimen. For example, by exposing the cross-section in the direction described later, a cross-sectional specimen capable of measuring the gap width can be prepared. The preparation of the cross-sectional specimen can be performed using known methods. Methods for preparing cross-sectional specimens include mechanical methods such as using a slicing machine to form the cross-section, methods such as FIB (fiber optic) plasma beam processing, and laser processing to apply energy to form the cross-section. Considering the hardness of materials commonly used as magnetic recording heads, FIB plasma beam processing is preferred for preparing the cross-sectional specimen. Furthermore, whether the non-physically separated but magnetically separated portions are composed of non-magnetic or magnetic materials can be determined using known methods, such as elemental and / or compositional analysis methods like energy-dispersive X-ray spectroscopy and Auger electron spectroscopy.

[0058] The following describes one method for forming a servo pattern for a magnetic recording head, which is an example of a magnetized region formed by the magnetic recording head on the magnetic layer of a magnetic recording medium (specifically, magnetic tape).

[0059] As a system that uses servo signals for head tracking (hereinafter referred to as a "servo system"), timing-based servo systems have been widely used in recent years. In a timing-based servo system, multiple servo patterns of two or more different shapes are formed on a magnetic layer. The position of the servo signal readout element is identified based on the time interval between reproducing (reading) two servo patterns of different shapes and the time interval between reproducing two servo patterns of the same type. In this invention and specification, "timing-based servo pattern" refers to a servo pattern that can be head-tracked in a timing-based servo system. In a timing-based servo system, the servo pattern that can be head-tracked is formed on a magnetic layer by a servo head, i.e., a servo write head, into multiple servo patterns of two or more different shapes. In one example, multiple servo patterns of two or more different shapes are arranged consecutively with a certain interval between multiple servo patterns of the same type. In another example, different types of servo patterns are arranged alternately. Regarding servo patterns of the same type, the degree of shape difference that may typically occur during the formation of the servo pattern is ignored. The shape of the servo pattern and the configuration on the servo tape in a timing-based servo system that can be head-tracked are well known, and the specific methods will be described later.

[0060] For example, in currently widely used linear recording methods, a timing-based servo system is typically employed. In magnetic tapes used in such systems, multiple regions (also called "servo tapes") with servo patterns are usually present along the length of the magnetic layer. The region sandwiched between two servo tapes is called the data tape. Data (magnetic signals) is recorded on the data tapes, forming multiple data tracks along the length of each data tape. Figure 1 The diagram shows an example of data band and servo band configuration. Figure 1 In this configuration, multiple servo bands 10 are arranged on the magnetic layer of magnetic tape 1, clamped by guard bands 12. Multiple areas 11 clamped by two servo bands are data bands. The servo pattern is a magnetized region formed by magnetizing specific areas of the magnetic layer using a servo writing head. The region magnetized by the servo writing head (the location where the servo pattern is formed) is determined according to specifications. For example, in LTO (Linear Tape-Open) Ultrium format magnetic tape, which is an industry standard specification, when the tape is manufactured, such as... Figure 2 As shown, multiple servo patterns are formed on the servo tape at an angle relative to the tape width direction. Specifically, in Figure 2In the servo frame SF on servo band 10, it consists of servo subframe 1 (SSF1) and servo subframe 2 (SSF2). Servo subframe 1 consists of A pulse train ( Figure 2 The middle part represents the symbol A) and the B pulse train ( Figure 2 The A pulse train is composed of servo patterns A1 to A5, and the B pulse train is composed of servo patterns B1 to B5. On the other hand, servo subframe 2 is composed of the C pulse train (… Figure 2 The symbol C is in the middle, and the D pulse train is in the middle. Figure 2 The C pulse train consists of servo patterns C1 to C4, and the D pulse train consists of servo patterns D1 to D4. These 18 servo patterns are arranged in groups of five and four in a servo subframe arranged in an array of 5, 5, 4, 4, and are used to identify the servo frame. Figure 2 The image shows a single servo frame. However, on each servo band, multiple servo frames are configured along the direction of travel. Figure 2 In the diagram, the arrows indicate the direction of the magnetic tape's travel. The side facing the direction of travel is the upstream side, and the opposite side is the downstream side.

[0061] Figure 3 and Figure 4 This is a diagram illustrating the azimuth angle α. In Figure 2 In the servo patterns shown, for servo patterns like servo patterns A1-A5 and C1-C4 that are tilted towards the upstream side in the direction of travel, the downstream edge E is... L The line segment connecting the two ends ( Figure 3 The dashed line L1 in the middle) and the band width direction ( Figure 3 The angle formed by the dashed line L2 in the diagram is the azimuth angle α. On the other hand, for servo patterns such as servo patterns B1~B5 and D1~D4 that are tilted towards the downstream side of the travel direction, the downstream edge E is... L The line segment connecting the two ends ( Figure 4 The dashed line L1 in the middle and the band width direction ( Figure 4 The angle formed by the dashed line L2 in the figure is the azimuth angle α.

[0062] A magnetic recording head that forms a servo pattern on the magnetic layer of a magnetic recording medium is a servo write head. The configuration of the write gap in a magnetic recording head (servo write head) used to form the servo pattern as described above is illustrated below. Figure 5 middle. Figure 5This is a schematic top view of the magnetic film viewed from the recording surface side of the magnetic recording head. Five pairs of write gaps, resembling a " / ", are arranged along the length direction L. Thus, a total of 10 write gaps WG (the blank areas in the figure) are provided on the magnetic film M of the magnetic recording head. Each write gap is inclined relative to the length direction at an azimuth angle α, the same as the servo pattern to be formed on the magnetic layer of the magnetic recording medium. During recording, at the position where a pulse current is applied to the surface of the magnetic layer of the magnetic recording medium to form the prescribed servo pattern, a leakage magnetic field is generated between the write gaps, thereby enabling the formation of a specific servo pattern on each of the five servo bands. Figure 2 The configuration shown is used to form servo patterns. For example, by applying a pulsed current, a pair of servo patterns (servo pattern A1 and servo pattern B1) can be formed from a pair of write gaps " / \", and servo patterns A2 and B2, A3 and B3, A4 and B4, A5 and B5, C1 and D1, C2 and D2, C3 and D3, and C4 and D4 can be formed sequentially. By repeating the formation of servo pattern pairs, multiple servo frames SF can be formed sequentially along the length direction of the servo band of the magnetic layer of the magnetic recording medium.

[0063] Figure 6A and Figure 6B This is an explanatory diagram of the measurement location for the gap width. For writing gaps tilted at azimuth angle α, the measurement direction for the gap width is set to a direction orthogonal to the azimuth direction. Figure 6A and Figure 6B In the diagram, dashed arrows indicate the azimuth direction, and solid arrows indicate the direction of gap width measurement. For a single write gap, as mentioned above, the width is measured at three locations. Similarly, for a single write gap, the width of the backside gap is also measured at three locations, as mentioned above. Figure 6A The diagram shows the write gaps used to form the servo patterns for the A-pulse and C-pulse trains. Figure 6B The diagram shows the write gaps used to form the servo patterns for the B and D pulse trains.

[0064] In the above description, a magnetic recording head (servo write head) for forming a servo pattern on the magnetic layer of a magnetic recording medium suitable for timing-based servo systems has been used as an example. However, the magnetic recording head described above is not limited to a magnetic recording head for forming timing-based servo patterns; for example, it could also be a magnetic recording head for forming a servo pattern capable of amplitude-based servo head tracking. For details regarding timing-based servo head tracking, for example, reference can be made to known technologies, primarily those described in U.S. Patent Nos. 5,689,384, 6,542,325, and 7,876,521. Furthermore, for details regarding amplitude-based servo head tracking, for example, reference can be made to known technologies, primarily those described in U.S. Patent Nos. 5,426,543 and 5,898,533. In one embodiment, the magnetic recording head described above can also be used as a magnetic recording head for data recording. For example, the above-mentioned magnetic recording head can also be used as a magnetic recording head for recording various information (data) on a magnetic layer of a magnetic recording medium on which a servo pattern has been formed.

[0065] In this invention and specification, "ion beam processing" refers to a process that forms an opening by irradiating an ion beam. The opening thus formed includes a through-hole extending from the recording surface of the magnetic film to the back surface, and a partial opening on the recording surface of the magnetic film that does not extend to the back surface. Regarding the determination that an opening is "an opening formed by ion beam processing," an opening formed by ion beam processing of a magnetic film by irradiating it with an ion beam is a physically open portion, i.e., a portion without magnetic or non-magnetic materials, and has the characteristic that the opening width narrows from the recording surface of the magnetic film towards the thickness direction. Furthermore, typically, on the recording surface of the magnetic film, a portion modified by ion irradiation (so-called burn marks) can be identified near the opening. This is because, typically, the processing target area for ion beam processing is designated based on scanning ion microscopy (SIM) images.

[0066] As described above, the openings formed on the magnetic film by ion beam processing have a characteristic where the opening width narrows from the recording surface of the magnetic film towards the thickness direction. Therefore, the write gap created solely by ion beam processing of the magnetic film has a wider gap width on the recording surface side than on the back surface side. On the recording surface side, where the gap width is wider, the magnetoresistance increases, making it difficult for the magnetic flux to converge. This is considered a reason for the reduced recording capability of the magnetic recording head.

[0067] In contrast, through repeated and in-depth research, the inventors have discovered a new method, for example, using the manufacturing method described below, that provides a magnetic recording head having an opening formed by ion beam processing at the gap end on the recording surface side, and the gap width on the recording surface side being narrower than the gap width on the back side. In such a magnetic recording head, it is believed that the magnetic field generated on the back side is more likely to become high-intensity, and the magnetic flux is relatively easier to converge to the recording surface side. It is speculated that this will help improve recording capability. However, the present invention is not limited to the speculations described in this specification.

[0068] In this invention and this specification, "magnetic" refers to strong magnetic properties, and "non-magnetic" refers to non-strong magnetic properties. As for magnetic properties, soft magnetic properties are preferred, and regarding non-magnetic properties, the relative permeability is preferably sufficiently close to 1.0 compared to general high-permeability materials.

[0069] The magnetic recording head described above will be explained in more detail below.

[0070] <Recording front side clearance width, back side clearance width>

[0071] In the above magnetic recording head, at least one write gap, preferably all write gaps, are narrow write gaps on the recording surface side, and the width of the record surface side gap is narrower than the width of the back side gap.

[0072] As described above, the recording surface-side gap width of the write gap, calculated as the arithmetic mean of the measured values ​​at all the narrow writing gaps on the recording surface side of the magnetic recording head, can, for example, be 0.1 μm or more, and preferably 0.2 μm or more, more preferably 0.5 μm or more, from the viewpoint of further improving recording capability. Furthermore, this recording surface-side gap width of the write gap can, for example, be 2.0 μm or less, and preferably 1.5 μm or less, more preferably 1.3 μm or less, from the viewpoint of further improving recording capability. Moreover, regarding each narrow writing gap on the recording surface side of the magnetic recording head, as described above, the recording surface-side gap width calculated as the arithmetic mean of the measured values ​​at three locations can also be within the above-described range, preferably within the above-described range.

[0073] On the other hand, in the aforementioned magnetic recording head, as described above, the back-side gap width of the writing gap, calculated as the arithmetic mean of the measured values ​​at all narrow writing gaps on the recording surface side included in the magnetic recording head, can, for example, be 1.0 μm or more, and preferably 2.0 μm or more, more preferably 5.0 μm or more, from the viewpoint of further improving recording capability. Furthermore, this back-side gap width of the writing gap can, for example, be 25.0 μm or less, and preferably 20.0 μm or less, more preferably 15.0 μm or less, from the viewpoint of further improving recording capability. Moreover, regarding each narrow writing gap on the recording surface side included in the aforementioned magnetic recording head, as described above, the back-side gap width calculated as the arithmetic mean of the measured values ​​at three locations can also be within the aforementioned range, preferably within the aforementioned range.

[0074] Furthermore, as described above, the ratio of the back side gap width of the write gap, calculated as the arithmetic mean of the measured values ​​on all recording surface narrow write gaps, to the recording surface gap width of the write gap (back side gap width / recording surface gap width), calculated as the arithmetic mean of the measured values ​​on all recording surface narrow write gaps, can exceed 1.0, preferably 1.5 or more, more preferably 2.0 or more, and even more preferably 5.0 or more. Moreover, the aforementioned ratio, for example, can be 60.0 or less, preferably 50.0 or less, more preferably 40.0 or less, even more preferably 30.0 or less, and even more preferably 20.0 or less. Furthermore, regarding each recording surface narrow write gap included in the magnetic recording head, as described above, the ratio of the back side gap width to the recording surface gap width (back side gap width / recording surface gap width), calculated as the arithmetic mean of the measured values ​​at the three locations, can also be within the aforementioned range, preferably within the aforementioned range.

[0075] <The end of the gap on the recording surface>

[0076] In the aforementioned magnetic recording head, at least one write gap, preferably all write gaps, are narrow write gaps on the recording surface side, with an opening formed by ion beam processing at the end of the gap on the recording surface side. According to ion beam processing, for example, as described in U.S. Patent No. 6,269,533 (Patent Document 1), fine gaps can be formed. However, if only ion beam processing is performed, as mentioned above, the recording surface side gap width becomes wider than the back side gap width, thus leading to a reduction in recording capability. In contrast, the aforementioned magnetic recording head has an opening formed by ion beam processing at the end of the gap on the recording surface side, but includes write gaps with a recording surface side gap width narrower than the back side gap width, thus enabling high recording capability. Details regarding the method for forming such write gaps will be described later.

[0077] The magnetic recording head described above will be explained in more detail below.

[0078] <Example of magnetic recording head configuration>

[0079] Hereinafter, an example of the configuration of the magnetic recording head described above will be described with reference to the accompanying drawings. However, the arrangement shown in the drawings is illustrative, and the present invention is not limited to this arrangement.

[0080] The aforementioned magnetic recording head can be a toroidal magnetic recording head or an inductive magnetic head. Inductive magnetic heads are also commonly referred to as electromagnetic induction heads or magnetic induction heads. Inductive magnetic heads generate a leakage magnetic field from the writing gap of the magnetic head core by allowing current to flow through the coil. This leakage magnetic field can form a magnetized region on the magnetic layer of the magnetic recording medium.

[0081] Figure 7 This is a perspective view showing an example of the aforementioned magnetic recording head. Figure 7 This is a three-dimensional view of the magnetic recording head as observed from the recording surface side. Figure 7 The magnetic recording head 20 shown has a head block 21, a shield 22, and a coil 25 (see reference). Figure 8 ).

[0082] The shield 22 is used to shield the coil 25 (reference) of the magnetic recording head 20. Figure 8 The shield 22 is a cover that generates a magnetic field and / or is used to shield magnetic fields from other external components. The shield 22 is a hollow cuboid-shaped cover made of a known material that can shield magnetic fields.

[0083] An opening 24 is provided on the upper part of the shield 22 to allow the magnetic head block 21 to protrude from the shield 22. Furthermore, an opening is provided on the lower part of the shield 22 to lead the wire 23 connected to the coil 25 to the outside of the shield 22.

[0084] Figure 8 yes Figure 7 The cross-sectional view of the magnetic recording head 20 shown. Figure 8 The sectional view shown is a sectional view in the width direction W, which is orthogonal to the length direction L of the magnetic recording head 20.

[0085] The magnetic head block 21 has a core 201 and a substrate 202 on which a magnetic film M is formed. When the core 201 is energized by the coil 25, the write gap of the magnetic film obstructs the magnetic flux passing through the magnetic film. As a result, a leakage magnetic field is generated at the location of the write gap. Through this leakage magnetic field, a magnetized region can be formed on the magnetic layer of the magnetic recording medium, i.e., recording is performed.

[0086] The material used to form the core 201 can be a magnetic material commonly used in the core of a toroidal magnetic recording head. Examples of magnetic materials include single-crystal ferrite, polycrystalline ferrite, and manganese-zinc ferrite. An opening 203 is formed near the center of the upper portion of the core 201 in the width direction, extending vertically along the length direction. The substrate 202 is disposed within the opening 203 to fill it.

[0087] Examples of materials that can be used as substrate 202 include non-magnetic materials (e.g., various glass materials, various ceramic materials).

[0088] Figure 9 yes Figure 8 This is a partially enlarged cross-sectional view of the magnetic recording head 20 shown. A writing gap WG is provided on the magnetic film M disposed on the substrate 202.

[0089] The magnetic film M can be a metal film. Here, "metal film" includes alloy films. The metal film can be a deposited film formed by depositing one or more metallic materials selected from the group consisting of one or more pure metals and one or more alloys, and may contain one or more additives, and / or may contain one or more unavoidably mixed impurities. The magnetic film M can be an iron alloy film. Here, "iron alloy" means "containing". The iron alloy film is preferably an iron nitride alloy film. Examples of iron nitride alloys include one or more alloys selected from the group consisting of Fe, N, Al, Ta, etc., as constituent elements. The magnetic film can be a deposited film in which a metallic material is deposited on a substrate by known film formation methods such as sputtering, vacuum evaporation, physical vapor deposition (PVD), and chemical vapor deposition (CVD).

[0090] The thickness of the magnetic film M can be, for example, 0.5 μm or more, and from the viewpoint of further improving recording capability, it is preferably 1.0 μm or more, and more preferably 3.0 μm or more. Furthermore, the thickness of the magnetic film M can be, for example, 12.0 μm or less, and from the viewpoint of the ease of forming a uniform magnetic film, it is preferably 10.0 μm or less, and more preferably 8.0 μm or less.

[0091] The thickness of the magnetic film is set as the thickness of a randomly selected portion of the magnetic film of the magnetic recording head that does not have a writing gap. A cross-sectional specimen including the portion of the magnetic film is prepared, and the thickness can be measured on this cross-sectional specimen. Specific examples of methods for preparing the cross-sectional specimen can be found in the above description. The measurement can be performed using a known measuring device with length measurement capabilities, such as an SEM.

[0092] Figure 10A and Figure 10B This is an enlarged cross-sectional view of the portion of the magnetic film containing the writing gap. The following will... Figure 10A and Figure 10B It is uniformly recorded as "Figure 10".

[0093] In Figure 10, the magnetic film M has a writing gap WG, where "a" represents the width of the gap on the recording surface side, "b" represents the thickness of the magnetic film, and "c" represents the width of the gap on the back side. The writing gap WG has an opening O formed by ion beam processing of the end of the gap on the recording surface side. Preferably, the opening formed by ion beam processing physically opens at least on the recording surface side and penetrates the magnetic film within the narrow writing gap on the recording surface side of the magnetic recording head. Figure 10 shows an example where the opening O extends to the back side. Alternatively, the opening formed by ion beam processing may not extend to the back side within the narrow writing gap on the recording surface side of the magnetic recording head. As will be explained later, this is because a magnetic spacing can be provided using a non-magnetic material portion.

[0094] Figure 10A The write gap WG shown has a non-magnetic material portion N at the gap end on the back side. Figure 10A A layer of non-magnetic material is provided in the middle. Figure 10B The write gap WG shown contains two layers (Non-magnetic material sections N1 and N2) of non-magnetic material. In the example shown in Figure 10, the cross-sectional shape of the non-magnetic material section is trapezoidal. However, the cross-sectional shape of the non-magnetic material section is not limited to this; it can also be any shape such as an arc, square, rectangle, or multi-level structure.

[0095] Examples of nonmagnetic materials constituting the nonmagnetic material section include silicon oxides (e.g., SiO2), titanate compounds (e.g., CaTiO3, BaTiO3), aluminum, and copper. Preferably, the nonmagnetic material constituting the nonmagnetic material section has a thermal expansion coefficient close to that of the material constituting the core. As mentioned above, ferrites are examples of materials constituting the core. From the viewpoint that the thermal expansion coefficient is close to that of ferrites, nonmagnetic oxides are preferred, and silicon oxides are more preferably used as the nonmagnetic material constituting the nonmagnetic material section.

[0096] The non-magnetic material portion can be a deposition film on a substrate formed by depositing non-magnetic materials on a known film formation method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD) using methods such as sputtering or vacuum evaporation. When a single write gap includes two or more layers of non-magnetic material portions, the non-magnetic materials constituting these non-magnetic material portions can be the same or different.

[0097] The thickness of the non-magnetic material portion (symbol "d" in FIG10) relative to the thickness of the magnetic film (symbol "b" in FIG10), i.e., with the thickness of the magnetic film as 100%, can be 3% or more. From the viewpoint of further improving recording capability, it is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more. The thickness of the non-magnetic material portion relative to the thickness of the magnetic film can, for example, be 95% or less. From the viewpoint of further improving recording capability, it is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. When there are two or more layers of non-magnetic material, the thickness of the non-magnetic material portion is set to the total thickness of these two or more non-magnetic material layers. Furthermore, the thickness of the non-magnetic material portion can, for example, be 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, and can be 10.0 μm or less, preferably 9.0 μm or less, and even more preferably 8.0 μm or less.

[0098] In the aforementioned magnetic recording head, at least one write gap, preferably all write gaps, are narrow write gaps on the recording surface side. The thickness of the non-magnetic material portion of the narrow write gaps on the recording surface side of the magnetic recording head refers to the arithmetic mean of the thicknesses of the non-magnetic material portions of all the narrow write gaps on the recording surface side of the magnetic recording head that have non-magnetic material portions. This arithmetic mean can be within the aforementioned range, preferably within the aforementioned range. The thickness of the non-magnetic material portion used to calculate the arithmetic mean of the thicknesses of each narrow write gap on the recording surface side having a non-magnetic material portion is measured at a randomly selected location of the non-magnetic material portion. A cross-sectional sample including the portion of the non-magnetic material portion is prepared, and the thickness of the non-magnetic material portion can be measured in this cross-sectional sample. The measurement can be performed using a known measuring device with length measurement capabilities, such as an SEM. Furthermore, the thickness of the non-magnetic material portion of each narrow write gap on the recording surface side having a non-magnetic material portion can also be within the aforementioned range, preferably within the aforementioned range.

[0099] In the example shown in Figure 10, the opening formed by ion beam processing penetrates the non-magnetic material portion. Therefore, an opening formed by ion beam processing also exists at the gap end on the back side. Since the gap width refers to the magnetic spacing width, the gap width on the back side is the width of the non-magnetic material portion (symbol "c" in Figure 10). Furthermore, the magnetic recording head described above is not limited to the form where the opening formed by ion beam processing penetrates the non-magnetic material portion; the non-magnetic material portion, including at least a portion at the gap end on the back side, also includes a solid portion without a physical opening.

[0100] A magnetic recording head having a narrow writing gap on the recording surface side, including the non-magnetic material portion as described above, can be manufactured, for example, by the manufacturing method described below.

[0101] [Manufacturing method of magnetic recording head]

[0102] The aforementioned magnetic recording head can be manufactured by a method comprising: forming a non-magnetic material portion on a substrate; forming a magnetic film on the substrate to cover the non-magnetic material portion; and forming an opening in a portion of the magnetic film where a write gap is to be formed by ion beam processing. The portion processed by the ion beam has the non-magnetic material portion between the magnetic film and the substrate. According to this manufacturing method, a magnetic recording head can be manufactured having an opening formed by ion beam processing at the gap end on the recording surface side and a write gap having a non-magnetic material portion at the gap end on the back side side.

[0103] Figure 11 express Figure 10A The diagram illustrates the method for forming the write gap. See below for reference. Figure 11 An example of the manufacturing method described above will be given. However, the manufacturing method described above is not limited to... Figure 11 As shown.

[0104] First, a non-magnetic material portion N is formed on a substrate 202 disposed within an opening 203 in the core 201. Figure 11 (a)). As a method for forming a non-magnetic material portion N on the substrate 202, one example is a method in which a continuous layer of non-magnetic material is formed on the substrate 202, and then a patterning method such as photolithography is used to form the non-magnetic material portion N as a pattern of non-magnetic material. The non-magnetic material constituting the non-magnetic material portion and its thickness are as described above. Regarding the film formation method of the continuous layer of non-magnetic material, the above description relating to the non-magnetic material portion of the write gap can be referred to. Since the width of the non-magnetic material portion N (pattern) is set to the back side gap width of the formed write gap, the back side gap width can be controlled by adjusting the size of the pattern.

[0105] like Figure 10B As exemplified, in the case where two or more layers of non-magnetic material are provided, for example, the following method can be used: after patterning a continuous layer of the first non-magnetic material, a second layer of non-magnetic material is formed as a pattern on the pattern of the formed non-magnetic material. Alternatively, patterning can be performed after two continuous layers of non-magnetic material are stacked.

[0106] Next, a magnetic film M is formed on the substrate 202 in such a way as to cover the non-magnetic material portion N. Figure 11 (b) Regarding the thickness and formation method of the magnetic film, as described above. Here, a magnetic film is formed not only on the substrate 202 but also on the surface of the core 201. Thus, as... Figure 9As shown, a magnetic film M can be provided on the recording surface side of the core 201.

[0107] Then, ion beam processing is performed by irradiating the surface of the magnetic film toward the recording surface side with an ion beam (IB). Figure 11 (c) This allows an opening to be formed. According to the characteristics of ion beam processing, the opening thus formed narrows in width towards the depth direction. However, as described above, since a non-magnetic material portion is provided, by making the width of the pattern of the non-magnetic material portion N greater than the opening width of the opening formed on the recording surface side by ion beam processing, a write gap with a recording surface side gap width narrower than the back surface side gap width can be formed.

[0108] Ion beam processing is a known process that creates openings by irradiating the workpiece with an ion beam. While ion beam processing can be performed using what is commonly known as ion milling, focused ion beam (FIB) processing is preferred from the perspective of processing accuracy. An ion beam is an ion beam accelerated in an electric field, and a focused ion beam is an ion beam focused by passing it through a lens or similar device. Focused ion beam processing is often also referred to as FIB processing. Focused ion beam processing can be performed using commercially available or known focused ion beam equipment. The processing conditions can be set according to the type of material and film thickness of the workpiece.

[0109] Further details regarding the aforementioned manufacturing method can be obtained using known techniques related to the manufacture of magnetic recording heads.

[0110] [Magnetic recording device]

[0111] One aspect of the present invention relates to a magnetic recording apparatus including the aforementioned magnetic recording head.

[0112] A magnetic recording device having a servo write head and forming a servo pattern on the magnetic layer of a magnetic recording medium via the servo write head is a servo writer. In one embodiment, the aforementioned magnetic recording device can be a servo writer.

[0113] Figure 12 This is a schematic diagram showing the structure of the servo writer. Figure 12 The servo writer 30 shown has a reel 31 for dispensing the magnetic tape 1 before servo pattern formation and a reel 32 for rewinding the magnetic tape 1 with the servo pattern formed. Figure 12The arrows in the diagram indicate the transport direction of magnetic tape 1. Multiple guides 33 and a tension adjustment device T for adjusting the tension of the transported magnetic tape 1 are arranged along the transport path of magnetic tape 1. A servo pattern is formed on the magnetic layer of the transported magnetic tape 1 by the magnetic recording head (servo writing head) 20. A write signal generation circuit 34 sends pulse signals to the magnetic recording head (servo writing head) 20 for forming the servo pattern. As a result, a leakage magnetic field is generated from the write gap WG of the magnetic recording head (servo writing head) 20, through which a magnetized region (servo pattern) can be formed on the magnetic layer of the magnetic recording medium.

[0114] [Manufacturing method of magnetic recording medium with servo pattern]

[0115] One aspect of the present invention relates to a method for manufacturing a magnetic recording medium having a servo pattern, comprising forming a servo pattern on the magnetic recording medium using the aforementioned magnetic recording head.

[0116] <Forming of Servo Patterns>

[0117] To form a servo pattern, for example, it is possible to use... Figure 12 The servo writer shown is an example. However, it is not limited to this.

[0118] In one approach, the resulting servo pattern can be a timing-based servo pattern. As shown in ECMA (European Computer Manufacturers Association) – 319 (June 2001), a timing-based servo method is used in magnetic tapes conforming to the LTO (Linear Tape-Open) specification (commonly referred to as "LTO tape"). In this timing-based servo method, the servo pattern is formed by arranging multiple non-parallel magnetic strips (also called "servo strips") continuously along the length of the tape. As mentioned above, the reason for forming the servo pattern with a pair of non-parallel magnetic strips is to inform the servo signal readout element passing over the servo pattern of its position. Specifically, the pair of magnetic strips is formed such that their spacing continuously varies along the width of the tape. By reading this spacing through the servo signal readout element, the relative position of the servo pattern and the servo signal readout element can be determined. This relative position information can be used to track data tracks. Therefore, typically, multiple servo tracks are arranged along the width of the tape on the servo pattern.

[0119] The servo tape consists of a continuous servo pattern along the length of the magnetic tape. Multiple servo tapes are typically arranged on the tape. For example, in an LTO tape, this number is five. The area sandwiched between two adjacent servo tapes is the data tape. The data tape consists of multiple data tracks, each corresponding to a servo track.

[0120] Furthermore, in one approach, as shown in Japanese Patent Application Publication No. 2004-318983, information indicating the servo band number (also known as "servo band ID" or "UDIM") is embedded in each servo band. This servo band ID is recorded by offsetting a specific servo band in a pair of servo strips that exist multiple times within the servo band, by relative displacement of its position along the length of the magnetic tape. Specifically, for each servo band, the offset of a specific servo strip in a pair of servo strips that exist multiple times is changed. Therefore, since the recorded servo band ID is unique for each servo band, the servo band can be uniquely identified by reading only one servo band from the servo signal reading element.

[0121] Alternatively, an interleaving method, as shown in ECMA-319 (June 2001), is used as a unique method for identifying servo tapes. In this interleaving method, for each servo tape, multiple pairs of non-parallel magnetic strips arranged consecutively along the length of the tape are recorded with offsets along the tape's length. The combination of these offsets between adjacent servo tapes is unique throughout the entire tape, thus allowing for unique identification of the servo tape when the servo pattern is read by two servo signal readout elements.

[0122] Furthermore, as shown in ECMA-319 (June 2001), each servo tape typically also embeds information indicating the position along the length of the tape (also known as "LPOS (Longitudinal Position) information"). Similar to UDIM information, this LPOS information is recorded by offsetting the position of a pair of servo strips along the length of the tape. However, unlike UDIM information, the LPOS information contains the same signals as each servo tape.

[0123] Other information, different from the UDIM and LPOS information mentioned above, can also be embedded in the server strip. In this case, the embedded information can be different for each server strip, like the UDIM information, or it can be universal for all server strips, like the LPOS information.

[0124] Furthermore, other methods besides those described above can also be used as a way to embed information in the servo strip. For example, a specified code can be recorded by pulling a specified pair from the middle of a pair of servo strips.

[0125] Before forming the servo pattern on the magnetic tape, the tape is typically demagnetized (erased). This erasure process can be performed by applying the same magnetic field to the tape using either a DC or AC magnet. There are two types of erasure processes: DC (Direct Current) erasure and AC (Alternating Current) erasure. AC erasure is performed by gradually decreasing the strength of the magnetic field while reversing its direction. DC erasure, on the other hand, is performed by applying a unidirectional magnetic field to the tape. There are two methods for DC erasure. The first method is horizontal DC erasure, which applies a unidirectional magnetic field along the length of the tape. The second method is vertical DC erasure, which applies a unidirectional magnetic field along the thickness of the tape. Erasure can be performed on the entire tape or on each servo section of the tape.

[0126] The direction of the magnetic field of the formed servo pattern is determined by the erasure direction. For example, when applying horizontal DC erasure to the magnetic tape, the servo pattern is formed such that the direction of the magnetic field is opposite to the erasure direction. This increases the output of the servo signal obtained by reading the servo pattern. Furthermore, as shown in Japanese Patent Application Publication No. 2012-53940, when a magnetic pattern is transferred using the aforementioned gap on a magnetic tape after vertical DC erasure, the servo signal obtained by reading the formed servo pattern is a unipolar pulse shape. On the other hand, when a magnetic pattern is transferred using the aforementioned gap on a magnetic tape after horizontal DC erasure, the servo signal obtained by reading the formed servo pattern is a bipolar pulse shape.

[0127] <Magnetic recording medium for forming servo patterns>

[0128] Magnetic recording media include tape magnetic recording media (i.e., magnetic tape) and disc magnetic tape (i.e., magnetic disk). Furthermore, magnetic recording media are generally broadly classified into coated type and metal film type. The magnetic recording media for forming servo patterns using the aforementioned magnetic recording head can be magnetic tape or magnetic disk, preferably magnetic tape. Moreover, the aforementioned magnetic recording media can be either coated type or metal film type. Magnetic recording media typically have a non-magnetic support and a magnetic layer containing strongly magnetic powder. A non-magnetic layer containing non-magnetic powder may be present between the non-magnetic support and the magnetic layer, or a back coating containing non-magnetic powder may be present on the surface of the non-magnetic support opposite to the surface with the magnetic layer. In coated type magnetic recording media, the magnetic layer, non-magnetic layer, and back coating contain a binder, and can arbitrarily contain one or more additives. Metal film type magnetic recording media may, for example, have a magnetic layer formed by sputtering.

[0129] The aforementioned magnetic recording head, having a writing gap including an opening formed by ion beam processing, and capable of high recording capability, is suitable as a magnetic recording head for recording on magnetic layers of magnetic recording media with high coercivity. Regarding the coercivity of the magnetic recording media, the aforementioned magnetic recording head is, for example, suitable for recording on magnetic layers of magnetic recording media with a vertical coercivity of 2800 Oe or more. More preferably, the aforementioned magnetic recording head is suitable for recording magnetic layers of magnetic recording media with a vertical coercivity of 3000 Oe or more, and even more preferably for recording magnetic layers of magnetic recording media with a vertical coercivity of 3500 Oe or more. The vertical coercivity of the magnetic recording media can, for example, be 5000 Oe or less. However, it can also exceed this value. The aforementioned magnetic recording head can also be applied to recording magnetic layers of magnetic recording media with low coercivity. Furthermore, regarding units, 1 Oe (1 Ørsted) = 79.6 A / m.

[0130] In this invention and specification, the "vertical coercivity" of the magnetic recording medium refers to the coercivity measured in the vertical direction of the magnetic recording medium. The "vertical direction" mentioned for coercivity refers to the direction orthogonal to the surface of the magnetic layer, and can also be called the thickness direction. In this invention and specification, the vertical coercivity of the magnetic recording medium is a value obtained using a vibrating sample type magnetometer by the following method.

[0131] A sample piece of the size suitable for insertion into a vibrating specimen magnetometer is cut from the magnetic recording medium to be measured. Using the vibrating specimen magnetometer, a magnetic field is applied perpendicularly to the sample piece (orthogonal to the surface of the magnetic layer) at a maximum applied magnetic field of 3979 kA / m, a measurement temperature of 296 K, and a magnetic field scan speed of 8.3 kA / m / s. The magnetization of the sample piece relative to the applied magnetic field is measured. The measured value is obtained by subtracting the background noise from the magnetization of the sample probe of the vibrating specimen magnetometer. The coercivity (vertical coercivity) is calculated from the applied magnetic field at which the magnetization becomes zero. The measurement temperature is the temperature of the sample piece. By setting the ambient temperature around the sample piece to 296 K, the temperature of the sample piece (measurement temperature) can be set to 296 K through temperature equilibrium.

[0132] Examples of strongly magnetic powders contained in the magnetic layer of a magnetic recording medium include hexagonal ferrite powder and ε-iron oxide powder.

[0133] In this invention and specification, "hexagonal ferrite powder" refers to a strongly magnetic powder whose hexagonal ferrite crystal structure, detected by X-ray diffraction analysis, is the main phase. The main phase refers to the structure to which the highest intensity diffraction peak in the X-ray diffraction spectrum obtained through X-ray diffraction analysis belongs. For example, if the highest intensity diffraction peak in the X-ray diffraction spectrum obtained through X-ray diffraction analysis belongs to a hexagonal ferrite crystal structure, then the hexagonal ferrite crystal structure is identified as the main phase. If only a single structure is detected by X-ray diffraction analysis, that detected structure is designated as the main phase. The hexagonal ferrite crystal structure contains at least iron atoms, divalent metal atoms, and oxygen atoms as constituent atoms. Divalent metal atoms refer to metal atoms that can become divalent cations as ions; examples include strontium atoms, barium atoms, calcium atoms, and other alkaline earth metal atoms, as well as lead atoms. In this invention and specification, "hexagonal strontium ferrite powder" refers to powder containing strontium atoms as the main divalent metal atom, and "hexagonal barium ferrite powder" refers to powder containing barium atoms as the main divalent metal atom. The main divalent metal atom refers to the divalent metal atom that constitutes the largest proportion of the divalent metal atoms in the powder, based on an atomic percentage. The aforementioned divalent metal atoms do not include rare earth atoms. In this invention and specification, "rare earth atoms" are selected from the group consisting of scandium (Sc), yttrium (Y), and lanthanides. The lanthanide atoms are selected from the group consisting of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and argonium (Lu).

[0134] In this invention and specification, "ε-iron oxide powder" refers to a strongly magnetic powder in which an ε-iron oxide crystal structure is detected as the main phase by X-ray diffraction analysis. For example, if the highest intensity diffraction peak in the X-ray diffraction spectrum obtained by X-ray diffraction analysis belongs to an ε-iron oxide crystal structure, it is determined that an ε-iron oxide crystal structure is detected as the main phase. ε-iron oxide powder includes substituted ε-iron oxide powder in which a portion of Fe is replaced by substituted atoms such as Ga, Co, Ti, Al, and Rh, and unsubstituted ε-iron oxide powder in which no such substituted atoms are present.

[0135] Further details regarding the magnetic recording medium that forms the servo pattern via the aforementioned magnetic recording head are available in the art.

[0136] Example

[0137] The present invention will now be described with reference to embodiments. However, the present invention is not limited to the embodiments shown in the examples.

[0138] [Making head A]

[0139] As the magnetic head A, it is manufactured Figure 8 , Figure 9 and Figure 10A The magnetic recording head shown in the example.

[0140] The core 201 is made of manganese-zinc ferrite, and the substrate 202 is made of silicon oxide.

[0141] On substrate 202, using SiO2 as a sputtering target, a continuous silicon oxide layer is formed by sputtering. Then, patterning is performed in a photolithography process to form a silicon oxide pattern N( Figure 11 (a)).

[0142] Then, a magnetic film (a continuous layer of Ta containing an iron nitride alloy (Fe content: 80 atomic percent or more)) is formed on substrate 202 by sputtering to cover the pattern N of silicon oxide. Figure 11 (b)).

[0143] After film deposition, to specify the processing area for FIB processing, a scanning ion microscope (SIM) is used to capture an image on the magnetic film surface on the recording surface side. Using this SIM image, the processing area is specified, and FIB processing is performed within that specified area using a focused ion beam apparatus. An opening is formed in the portion of the magnetic film where a writing gap should be formed (the portion containing the silicon oxide pattern N between the magnetic film and the substrate). Figure 11 (c)). FIB processing is performed under the following conditions.

[0144] Focused Ion Beam System: Manufactured by Hitachi High-Tech Co., Ltd. FB-2200

[0145] Accelerating voltage: 30kV

[0146] Focusing lens: Yes

[0147] Pore ​​size: 80μm

[0148] DWell Time (Irradiation time per pixel): 5 microseconds

[0149] Thus, with Figure 5 The configuration shown produces a magnetic recording head with a total of 10 write gaps WG. The five write gaps in the " / " shape are produced under the same conditions, and the five write gaps in the "\" shape are produced under the same conditions.

[0150] [Making of magnetic heads B-N]

[0151] The width 'a' of the recording surface side gap in the writing gap can be adjusted according to the processing conditions of FIB processing.

[0152] The thickness b of the magnetic film can be adjusted by changing the film formation conditions of the sputtering method.

[0153] The back side gap width c corresponds to the width of the pattern of silicon oxide formed by patterning, and can therefore be adjusted according to the patterning conditions.

[0154] The thickness d of the non-magnetic material section can be adjusted by changing the film formation conditions of the sputtering method when forming a continuous silicon oxide layer.

[0155] Except for changing one or more of the above-mentioned points, magnetic heads B to N are manufactured in the same way as magnetic head A.

[0156] [Making the magnetic head O]

[0157] Except that, after patterning the first layer of silicon oxide in the same manner as with magnetic head A, the silicon oxide is patterned on this pattern by sputtering, and a pattern with [missing information] is fabricated in the same manner as with magnetic head A. Figure 10B The example shows the write gap of the head O.

[0158] [Making the magnetic head P]

[0159] Except that the magnetic film is formed directly on the substrate 202 without the need for continuous layer deposition and patterning of silicon oxide, the magnetic head P is manufactured in the same manner as the magnetic head A.

[0160] Using the method described above, multiple magnetic heads A through P are manufactured. Of these multiple magnetic heads, one will be used for the various measurements described below, and another will be used for the recording experiments described below.

[0161] [Various measurements]

[0162] <Recording surface side gap width a>

[0163] Observing each magnetic head A to P from the recording plane side, and using a laser microscope (KEYENCE CORPORATION, VK-8700), the width of the gap in the recording plane side end portion (i.e., the opening width in the recording plane side end portion of the opening formed by FIB processing) was measured in three locations: near the center, near one end portion (approximately 10 μm from the end portion), and near the other end portion (approximately 10 μm from the end portion), in a direction orthogonal to the azimuth direction. The measurement conditions were set as follows: objective lens magnification: 150x, measurement step in the XY direction: 0.01 μm.

[0164] Calculate the arithmetic mean of the measured values ​​obtained for the 10 writing gaps (totaling 10 × 3 = 30). The calculated value is shown in Table 1 as the recording surface side gap width 'a'.

[0165] Furthermore, for each of the 10 write gaps, the arithmetic mean of the measured values ​​obtained by measuring at three locations is also the value shown in Table 1.

[0166] <Thickness b of the magnetic film>

[0167] Cross-sectional specimens of each magnetic head (A-P) were fabricated. The thickness of the magnetic film was measured by SEM at a randomly selected location within the non-writing gap portion of the fabricated specimens under the following conditions. The following conditions were also used as the measurement conditions for the SEM described later. The measured values, denoted as the thickness b of the magnetic film, are shown in Table 1.

[0168] Device: Manufactured by Hitachi High-Tech Co., Ltd. s-4800

[0169] Accelerating voltage: 5kV

[0170] Magnification: Within the range of 100 to 2000x, select the magnification range where the object being measured usually falls appropriately within the field of view of the SEM.

[0171] Measurement: Measured by comparison with the scale displayed on the SEM.

[0172] <Back side gap width c>

[0173] In each of the magnetic heads A to O, for the 10 write gaps, cross-sectional samples were made by exposing the cross-section in a direction orthogonal to the azimuth direction at three locations: near the central part, near one end (about 10 μm from the end), and near the other end (about 10 μm from the end). Using these cross-sectional samples, the gap width (i.e., the width of the non-magnetic material part (c in Figure 10)) in the back side end part in a direction orthogonal to the azimuth direction was measured by SEM.

[0174] In the magnetic head P, for the 10 write gaps, cross-sectional specimens are made by exposing the cross-section in a direction orthogonal to the azimuth direction at three locations: near the central part, near one end (about 10 μm from the end), and near the other end (about 10 μm from the end). Using these cross-sectional specimens, the gap width in the back side end portion in the direction orthogonal to the azimuth direction (i.e., the opening width in the back side end portion of the opening formed by FIB processing) is measured by SEM.

[0175] Calculate the arithmetic mean of the measured values ​​obtained for the 10 write gaps (totaling 10 × 3 = 30). The calculated value is shown as the back side gap width c in Table 1.

[0176] Furthermore, for each of the 10 write gaps, the arithmetic mean of the measured values ​​obtained by measuring at three locations is also the value shown in Table 1.

[0177] <Thickness d of the non-magnetic material section>

[0178] For magnetic heads A to O, the thickness d of the non-magnetic material part is determined by the following method.

[0179] For each of the 10 write gaps in each magnetic head, a cross-sectional sample was fabricated at a randomly selected location. The thickness of the non-magnetic material portion (silicon oxide) in the cross-sectional sample was measured by SEM.

[0180] Calculate the arithmetic mean of the measured values ​​obtained for the 10 writing gaps (totaling 10 × 1 = 10). The calculated value is shown as the thickness d of the non-magnetic material section in Table 1.

[0181] Furthermore, for each of the 10 write gaps, the measured values ​​obtained by measuring at the aforementioned location 1 are also the values ​​shown in Table 1.

[0182] [Record the experiments (Experiments 1-22, Reference Experiment 1, Comparative Experiment 1)]

[0183] Recording experiments were conducted to evaluate whether saturation recording was possible using the magnetic head and magnetic tape combinations shown in Table 1. In the experiments, magnetic tape was transported using... Figure 12 The servo writer with the structure shown uses the same playback head as the LTO-Gen (Generation) 8 driver. When the pulse current value is continuously increased from 10mA to 50mA, the playback signal obtained from the magnetic tape is measured. Even without increasing the pulse current value, the amplitude of the playback signal does not increase but begins to decrease slightly, thus indicating saturation recording. Cases indicating saturation recording are marked as "OK," and cases not marked as "NG." The test results are shown in Table 1.

[0184] In Table 1, "BaFe" in the "Strong Magnetic Powder of Magnetic Recording Medium" column indicates hexagonal barium ferrite powder, and "SrFe" indicates hexagonal strontium ferrite powder. The magnetic recording media shown in Table 1 are coated magnetic tapes, which have a non-magnetic layer and a magnetic layer sequentially on one surface of the non-magnetic support, and a back coating on the other surface.

[0185] The vertical coercivity of the magnetic recording media in Table 1 was determined using the following method.

[0186] Sample pieces were cut from each magnetic tape. For these sample pieces, a TM-TRVSM5050-SMSL type vibratory magnetometer was used, manufactured by TAMA GAWALtd., and the vertical coercivity was determined using the method described above.

[0187] The results are shown in Table 1 (Table 1-1, Table 1-2).

[0188]

[0189]

[0190] In the magnetic head P, all 10 write gaps are created by FIB processing, forming openings on the magnetic film to serve as through holes. When the cross-sectional sample prepared above was observed by SEM, the cross-sectional shape of the through holes formed by FIB processing of each write gap was an inverted cone shape with the opening width narrowing from the recording surface side to the back surface side.

[0191] In magnetic heads A to O, each of the 10 write gaps has an opening formed by FIB machining at the end of the gap on the recording surface side. This opening is a through hole extending to the back side. When the cross-sectional sample prepared above was observed by SEM, the cross-sectional shape of the through hole formed by FIB machining of each write gap was an inverted cone shape with the opening width narrowing from the recording surface side to the back side. However, due to the presence of a non-magnetic material portion, the gap width on the recording surface side is narrower than the gap width on the back side in all 10 write gaps. As shown in Table 1, these magnetic heads A to O can perform saturation recording on magnetic tapes with coercivity exceeding that of magnetic head P (Comparative Test Example 1).

[0192] Furthermore, in the results shown in Table 1, the higher the recording capability, the better the magnetic head can be saturated for recording magnetic tapes with higher coercivity in the vertical direction.

[0193] Furthermore, when observing the area near the opening formed by FIB processing on the magnetic film surface of the recording surface in magnetic heads A to P using an optical microscope, it was confirmed that the area modified by ion irradiation (so-called burn marks) was identified when the area to be processed by FIB processing was photographed using a scanning ion microscope (SIM) to specify the processing target area.

[0194] Industrial availability

[0195] One aspect of the present invention is useful in the field of magnetic recording for high-density recording.

Claims

1. A magnetic recording head having a magnetic film including a writing gap, In the write gap, the width of the gap on the recording surface is narrower than the width of the gap on the back surface, and The gap end on the recording surface side of the writing gap has an opening, and, The writing gap includes a non-magnetic material portion at the gap end on the back side.

2. The magnetic recording head according to claim 1 is a servo writing head.

3. The magnetic recording head according to claim 1 or 2, wherein, The width of the writing gap on the recording surface side is greater than 0.2 μm and less than 1.5 μm.

4. The magnetic recording head according to claim 1 or 2, wherein, The width of the back side gap of the writing gap is greater than 2.0 μm and less than 20.0 μm.

5. The magnetic recording head according to claim 1 or 2, wherein, The thickness of the magnetic film is greater than 1.0 μm and less than 10.0 μm.

6. The magnetic recording head according to claim 1 or 2, wherein, The thickness of the non-magnetic material portion is 5% or more and 90% or less relative to the thickness of the magnetic film.

7. The magnetic recording head according to claim 1 or 2, wherein, The non-magnetic material constituting the non-magnetic material portion is silicon oxide.

8. The magnetic recording head according to claim 1 or 2, wherein, The magnetic film is an iron nitride alloy film.

9. A magnetic recording device comprising the magnetic recording head according to any one of claims 1 to 8.

10. The magnetic recording device according to claim 9, wherein it is a servo writer.

11. A method for manufacturing a magnetic recording head, comprising the method for manufacturing a magnetic recording head according to any one of claims 1 to 8, the method comprising: A non-magnetic material portion is formed on the substrate; A magnetic film is formed on the substrate to cover the non-magnetic material portion; and An opening is formed in the portion of the magnetic film where a writing gap should be formed by ion beam processing. The portion undergoing the ion beam processing has the non-magnetic material portion between the magnetic film and the substrate.

12. The method for manufacturing a magnetic recording head according to claim 11, wherein, The ion beam processing is focused ion beam processing.

13. A method for manufacturing a magnetic recording medium having a servo pattern, comprising the following steps: forming a servo pattern on the magnetic recording medium using a magnetic recording head as described in any one of claims 1 to 8.

14. The method for manufacturing a magnetic recording medium according to claim 13, wherein, The servo pattern is a timing-based servo pattern.

15. The method for manufacturing a magnetic recording medium according to claim 13 or 14, wherein, The vertical coercivity of the magnetic recording medium is above 2800 Oe.

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