Sputtering target, method for manufacturing laminated film, laminated film, and magnetic recording medium

Abstract

The invention provides a sputtering target capable of maintaining high coercive force in a magnetic layer of a magnetic recording medium and improving magnetic separability between magnetic particles. The sputtering target contains Co and Pt as metal components and NbO2 as a metal oxide component. Alternatively, the sputtering target contains Co and Pt as metal components, and has a phase containing Co, Nb, and O.

Description

Technical Field

[0001] The present invention relates to a sputtering target. In addition, the present invention relates to a method for producing a laminated film using the sputtering target of the present invention. Furthermore, the present invention relates to a laminated film and a magnetic recording medium. Background Art

[0002] In hard disk drives, a perpendicular magnetic recording method for recording magnetic fields in a direction perpendicular to a recording surface has been put into practical use. This method is widely used because it can achieve higher density recording than conventional in-plane magnetic recording methods.

[0003] The perpendicular magnetic recording magnetic recording medium is generally composed of a bonding layer, a soft magnetic layer, a seed layer (Seed layer), a base layer such as a Ru layer, an intermediate layer, a magnetic layer, and a protective layer stacked in sequence on a substrate such as aluminum or glass. Among them, the magnetic layer, at the bottom, has a granular film of SiO2 or other metal oxides dispersed in a Co-Pt alloy with Co as the main component, and has a high saturation magnetization Ms and magnetic anisotropy Ku. In addition, the intermediate layer stacked on the lower side of the magnetic layer is composed of a structure in which the same metal oxide is dispersed in a Co-Cr-Ru alloy, and sometimes contains more Ru, Cr, etc. in order to obtain non-magnetic properties.

[0004] In such a magnetic layer and an intermediate layer, the above-mentioned metal oxide serving as a nonmagnetic material precipitates toward the grain boundaries of magnetic grains such as Co alloy oriented in the vertical direction, thereby reducing the magnetic interaction between the magnetic grains, thereby achieving improved noise characteristics and high recording density.

[0005] It should be noted that, generally, each layer such as the magnetic layer and the intermediate layer is formed by sputtering a sputtering target having a predetermined composition or structure onto a substrate to form a film. As such a technology, there is a technology described in Patent Document 1 (Japanese Patent No. 5960287).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 5960287 Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] It is worth mentioning that in order to realize high density of hard disk drives, it is necessary to increase the magnetic anisotropy Ku to ensure the thermal stability of the recording layer formed in the magnetic recording medium, and to have high magnetic separability of magnetic particles in the recording layer to obtain high resolution.

[0011] However, in the magnetic layer that realizes high magnetic anisotropy Ku and has high saturation magnetization Ms as described above, the exchange bonding between the magnetic particles is very strong, so the magnetic separation between the magnetic particles is insufficient. On the other hand, if a large amount of metal oxide is added to improve the magnetic separation, the metal oxide will enter the magnetic particles and the crystallinity of the magnetic particles will deteriorate, and the saturation magnetization Ms and the magnetic anisotropy Ku will decrease, and the coercive force Hc will decrease. In addition, in order to increase the magnetic anisotropy Ku, there is a method of increasing the substrate temperature during film formation, but this will also lead to a decrease in the magnetic separation between the magnetic particles and a decrease in the coercive force Hc. In order to achieve high density, it is important to have both high coercive force Hc of the recording layer and magnetic separation between the magnetic particles in the recording layer.

[0012] The present invention is made in view of the above problems. In one embodiment, the technical problem to be solved is to provide a sputtering target that can maintain a high coercive force Hc in the magnetic layer of a magnetic recording medium and improve the magnetic separation between magnetic particles. In addition, in another embodiment, the present invention aims to provide a method for manufacturing a laminated film using such a sputtering target, a laminated film, and a magnetic recording medium.

[0013] Solutions to technical problems

[0014] The inventors of the present invention have found through in-depth research that the metal oxide of the non-magnetic material dispersed in the Co alloy of the magnetic material of the magnetic layer contains Nb as an oxide in a characteristic form, which can significantly improve the magnetic separation between magnetic particles. In addition, it was found that the high coercive force Hc of the magnetic layer mainly composed of Co-Pt can be maintained. The present invention is completed based on the above knowledge, as exemplified below. [1]

[0016] A sputtering target contains Co and Pt as metal components and contains NbO2 as a metal oxide component. [2]

[0018] The sputtering target as described in [1], wherein the content of NbO2 is 0.5 mol% to 30 mol%. [3]

[0020] A sputtering target contains Co and Pt as metal components and has a phase containing three elements of Co, Nb and O. [4]

[0022] The sputtering target according to [3], wherein a diffraction peak is observed at 2θ=30.27°±1° when measured using an X-ray diffractometer. [5]

[0024] The sputtering target according to [4], wherein a diffraction peak is observed at 2θ=30.27°±1° when measured under the following conditions:

[0025] (1) The analysis position of the sputtering target is the cross section perpendicular to the sputtering surface;

[0026] (2) Using Cu-Kα as the X-ray source;

[0027] (3) The tube voltage is 40 kV;

[0028] (4) The tube current is 30mA;

[0029] (5) The divergence slit is 1°;

[0030] (6) The divergence longitudinal limiting slit is 10 mm;

[0031] (7) The scattering slit is 8 mm;

[0032] (8) The light receiving slit is in an open state;

[0033] (9) The goniometer uses a horizontal specimen type;

[0034] (10) Scanning speed is 10° / min;

[0035] (11) The scanning step is 0.01°;

[0036] (12) The measurement range is 2θ = 20° to 80°;

[0037] (13) Background removal using fitting method;

[0038] (14) The analysis position is ground using #2000 water-resistant abrasive paper, and then polished using a slurry in which aluminum oxide abrasive particles with a particle size of 0.3 μm are dispersed;

[0039] (15) The flat surface with little unevenness in the analysis position is measured. [6]

[0041] A sputtering target as described in any one of [1] to [5], wherein as a metal oxide component, it also contains at least one metal oxide selected from TiO2, SiO2, Cr2O3, B2O3, CoO and Co3O4, and the total content of the metal oxides in the sputtering target is 20 vol% to 60 vol%. [7]

[0043] The sputtering target according to any one of [1] to [6], wherein the content of Pt is 2 mol % to 25 mol %. [8]

[0045] A method for producing a laminated film, comprising: forming a magnetic layer on a base layer containing Ru by sputtering using the sputtering target described in any one of [1] to [7]. [9]

[0047] A laminated film comprises: a base layer containing Ru, and a magnetic layer formed on the base layer and containing Co and Pt as metal components; the magnetic layer contains NbO2 as a metal oxide component.

[10]

[0049] The laminated film as described in [9], wherein the magnetic layer further contains at least one metal oxide of TiO2, SiO2, Cr2O3, B2O3, CoO and Co3O4 as a metal oxide component.

[11]

[0051] A magnetic recording medium comprising the laminated film according to [9] or

[10] .

[0052] Effects of the Invention

[0053] According to one embodiment of the present invention, a sputtering target can be provided that can maintain a high coercive force in a magnetic layer of a magnetic recording medium and improve the magnetic separation between magnetic particles. In addition, according to another embodiment of the present invention, a method for manufacturing a laminated film using such a sputtering target, a laminated film, and a magnetic recording medium can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 Schematic diagram showing the layer structure of a laminated film produced by an example of the present invention.

[0055] Figure 2 This is a diagram showing the results of XRD measurement of the target in the example of the present invention. DETAILED DESCRIPTION

[0056] The present invention is not limited to the following embodiments, and it should be understood that appropriate changes and improvements in design can be made based on the common knowledge of those skilled in the art without departing from the scope of the present invention.

[0057] The sputtering target of the present embodiment is characterized in that it contains Co and Pt as metal components and contains NbO2 as a metal oxide component. More specifically, the sputtering target of the present embodiment has a structure in which a metal oxide containing Nb oxide is dispersed in an alloy of Co and Pt. It should be noted that when a metal oxide component is mentioned in this specification, unless otherwise specifically denied, it is a description of the metal oxide as a raw material of the sputtering target.

[0058] The sputtering target is particularly preferably used for forming a magnetic layer located on an intermediate layer of a magnetic recording medium of a perpendicular magnetic recording method. In this case, in the magnetic layer formed by sputtering using the sputtering target, the above-mentioned metal component constitutes magnetic particles, and the metal oxide containing NbO2 becomes a non-magnetic material and is uniformly distributed around the magnetic particles oriented in the perpendicular direction, effectively reducing the magnetic interaction between the magnetic particles.

[0059] (1. Components)

[0060] The metal component of the sputtering target is mainly composed of Co and further contains Pt. In particular, the metal component is a Co alloy containing Pt.

[0061] The content of Pt is preferably 2 mol% to 25 mol%. When the total content of Pt is too much, the magnetic anisotropy may be reduced and the crystallinity of the magnetic particles may be deteriorated. On the other hand, when the ratio of the total content of Pt to Co is too low, the magnetic anisotropy may be insufficient. It should be noted that, for example, the content of Pt in the sputtering target can be determined based on the analysis results by ICP analysis.

[0062] The sputtering target of this embodiment can also contain Cr, Ru, Ti, Cu, Ta, W, V, Rh, etc. as non-magnetic metal components. By also containing such metals, it has the advantage of being able to adjust the saturation magnetization and magnetic anisotropy while maintaining the crystallinity of the magnetic particles. It should be noted that although most of such metals are usually contained in the form of metal components, they will be oxidized during sintering during the manufacture described below, so a part of them is contained in the form of metal oxides.

[0063] Furthermore, the sputtering target of the present embodiment contains at least NbO 2 as a metal oxide component. By containing NbO 2, the magnetic separation between magnetic grains can be improved while maintaining the coercive force.

[0064] Although it is not intended to limit the present invention by theory, Nb oxide has the following advantages: it has suitable wettability with Co, and can become a stable oxide even if a part of oxygen is missing, so the oxide does not enter the magnetic particles but forms a grain boundary with a uniform width around the magnetic particles. The inventors have also observed the following phenomenon: when Nb oxide with a smaller oxidation number is used, the advantage becomes obvious. It is believed that this is because it can form a composite oxide with Co, so the wettability with Co becomes better. Therefore, by containing NbO2 with a smaller oxidation number among Nb oxides, magnetic separation between magnetic particles that cannot be achieved by the prior art can be achieved.

[0065] In the sputtering target of the present embodiment, the content of NbO2 is preferably 0.5mol% to 30mol% compared to the total composition of the raw material of the sputtering target. When the content of NbO2 is 0.5mol% or more, the effect of improving the magnetic separation between magnetic particles can be reliably obtained. On the other hand, the content of NbO2 is preferably 30mol% or less based on the viewpoint that the effect reaches the upper limit and the saturation magnetization and magnetic anisotropy of the magnetic film are ensured and a higher coercive force is obtained. Based on this viewpoint, the content of NbO2 is preferably 20mol% or less, and more preferably 10mol% or less.

[0066] In addition, the sputtering target of the present embodiment can contain at least one of TiO2, SiO2, Cr2O3 and B2O3 as a metal oxide component in addition to NbO2. Thus, in addition to the effect of the above-mentioned NbO2, the effect of the metal oxide of TiO2, SiO2, Cr2O3 or B2O3 can be obtained. In addition, as a metal oxide component, CoO and Co3O4 can be contained. By adding these Co oxides, the effect of NbO2 can be improved.

[0067] In the case of containing metal oxides as described above except NbO2, the total content of metal oxides present in the sputtering target, that is, the metal oxides constituting the organizational structure of the sputtering target, is preferably 20 vol% to 60 vol%. If the total content of metal oxides is 20 vol% or more, the magnetic separation between magnetic particles can be fully ensured. On the other hand, if the total content of metal oxides is 60 vol% or less, the reduction of coercive force can be prevented. For this reason, the total content of metal oxides is more preferably 30 vol% to 55 vol%. It should be noted that, for example, an image of the surface of the sputtering target is obtained using SEM, and the particles in the image are classified into metal particles and metal oxide particles by EDS analysis. Based on the area ratio of metal particles to metal oxide particles, the volume ratio of metal oxides present in the sputtering target can be estimated. In addition, the content of metal oxides can be estimated not only by observing the surface of the sputtering target, but also based on the density and weight of the raw material powder. The calculation method based on the raw material powder is as described below.

[0068] (2. Method for manufacturing sputtering target)

[0069] The above-mentioned sputtering target can be produced by using a powder sintering method, and a specific example thereof is as follows.

[0070] First, as metal powder, Co powder and Pt powder are prepared, and powders of other metals mentioned above are prepared as needed. The metal powder can be not only a single element but also an alloy powder. Based on the viewpoint of being able to achieve uniform mixing and preventing segregation and coarse crystallization, it is preferred that the particle size is in the range of 1 μm to 10 μm. When the particle size of the metal powder is greater than 10 μm, there is a possibility that the oxide particles described below are not evenly dispersed. In addition, when the particle size is less than 1 μm, there is a possibility that the sputtering target deviates from the required component due to the influence of oxidation of the metal powder.

[0071] In addition, as oxide powder, at least NbO2 powder is prepared, and at least one powder selected from the group consisting of TiO2, SiO2, Cr2O3 and B2O3 is prepared as needed. The oxide powder preferably has a particle size in the range of 1 μm to 30 μm. Thus, when mixed with the above-mentioned metal powder and pressure sintered, the oxide particles can be more uniformly dispersed in the metal phase. When the particle size of the oxide powder is greater than 30 μm, coarse oxide particles may be generated after pressure sintering. On the other hand, when the particle size is less than 1 μm, aggregation of the oxide powders may occur.

[0072] Next, the above-mentioned metal powder and oxide powder are weighed into the required components. Here, for example, the NbO2 powder is weighed in a manner that the total composition of the raw material of the sputtering target is 0.5mol% to 30mol%. It should be noted that it is preferred to weigh the NbO2 powder in a manner that the total composition is 0.5mol% to 20mol%, and it is more preferred to weigh it in a manner that the NbO2 powder is 0.5mol% to 20mol%. In addition, when weighing, for example, the Pt powder is weighed in a manner that the total composition of the raw material is 2mol% to 25mol%. Further, when weighing, the oxide powder used as the raw material is weighed in a manner that the total content of the metal oxide in the sputtering target is 20vol% to 60vol%. And, using a known method such as a ball mill, the weighed metal powder and oxide powder are mixed and crushed. At this time, it is preferred to fill the inside of the container used in mixing and crushing with an inert gas to suppress the oxidation of the raw material powder as much as possible. Thus, a mixed powder in which the specified metal powder and oxide powder are uniformly mixed can be obtained.

[0073] Then, the mixed powder thus obtained is pressed and sintered in a vacuum atmosphere or an inert atmosphere to be formed into a predetermined shape such as a disk. Here, various pressure sintering methods such as hot pressing sintering, hot isostatic pressing sintering, and plasma discharge sintering can be used. Among them, hot pressing sintering is effective from the viewpoint of increasing the density of the sintered body.

[0074] The holding temperature during sintering is in the range of 700°C to 1500°C, and is particularly preferably 800°C to 1400°C. Furthermore, the holding time at the temperature in this range is preferably 1 hour or more. In addition, the applied pressure during sintering is preferably 10MPa to 40MPa, and more preferably 25MPa to 35MPa. Thus, a sintered body in which oxide particles are more uniformly dispersed in the metal phase while maintaining a high density can be produced.

[0075] The sintered body obtained by the pressure sintering described above can be subjected to cutting and other machining processes to form the sintered body into a desired shape using a lathe or the like, thereby manufacturing a sputtering target.

[0076] (3. Organization structure of sputtering target)

[0077] The sputtering target of the present embodiment contains NbO 2 as a metal oxide component of a raw material. Corresponding to this feature, one of the features of the sputtering target is that it has a phase containing three elements of Co, Nb, and O.

[0078] Although the present invention is not limited by theory, it is speculated that the magnetic particles in the thin film produced using the target having the three phases of Co, Nb and O can form oxide grain boundaries with uniform width around them, thereby improving the magnetic separation between the magnetic particles. Such a phase is a phase unique to the sputtering target containing NbO2 as a metal oxide component.

[0079] The phase containing Co, Nb and O can be confirmed by X-ray diffraction (XRD), for example. That is, in the XRD spectrum using Cu-Kα, there is a diffraction peak around 2θ=30.27°±1°. Figure 2 In the description of the diffraction peak, it is pointed out that the diffraction peak corresponds to the peak of CoNb2O6, but it can be considered that it may be, for example, CoNb2O 6-δ (δ>0), that is, there is a possibility that the oxygen content is slightly less. The phase including these is regarded as a phase containing Co, Nb and O. It is considered that this phase is formed by the reaction of Co and NbO2.

[0080] Thus, in the present embodiment, as a method for verifying that NbO 2 is contained in the raw material as a metal oxide component, there is a method of confirming the presence or absence of a phase containing three components of Co, Nb, and O.

[0081] It should be noted that, although in the case of a phase containing Co, Nb and O, it can be inferred that the metal oxide as the raw material contains NbO2, for example, when the NbO2 of the raw material does not react with other metal components and / or oxides in this way during the manufacturing process, theoretically, there is a possibility that the phase containing Co, Nb and O cannot be detected. In addition, in the case where the sputtering target contains NbO2 as a metal oxide component, it is possible to detect the diffraction peak corresponding to NbO2 by XRD. At least in this case, it can be said that NbO2 that constitutes its organizational structure exists in the sputtering target. However, in the process of sintering the raw material powder, almost all of the NbO2 reacts with other metal components and / or oxides to form other compounds, so there is a possibility that the diffraction peak corresponding to NbO2 cannot be detected from the sputtering target.

[0082] (4. Laminated body)

[0083] The laminated film comprises at least an underlayer and a magnetic layer formed on the underlayer. More specifically, the underlayer contains Ru, is usually composed of Ru, or has Ru as its main component.

[0084] The magnetic layer contains Co and Pt as metal components and Nb oxide as a metal oxide component. The magnetic layer contains Nb oxide, which can improve the magnetic separation between magnetic particles. The magnetic layer can be formed by sputtering a sputtering target having the above-mentioned NbO2 phase and / or a phase containing Co, Nb and O on the base layer.

[0085] Therefore, the magnetic layer, like the above-mentioned sputtering target, preferably has a NbO2 content of 0.5 mol% to 30 mol%. When it also contains at least one metal oxide selected from the group consisting of TiO2, SiO2, Cr2O3, B2O3, CoO and Co3O4 as a metal oxide component, the total content of metal oxides including NbO2 is preferably 20 vol% to 60 vol%, preferably contains 2 mol% to 25 mol% of Pt, and preferably also contains 0.5 mol% to 20 mol% of Cr and / or Ru as metal components.

[0086] Each layer of the laminated film can be formed by forming a film using a magnetron sputtering device or the like using a sputtering target having a composition and a structure corresponding to each of these layers.

[0087] The magnetic layer of the laminated film can be formed on the base layer by performing film formation by sputtering using the sputtering target as described above.

[0088] (5. Magnetic recording media)

[0089] The magnetic recording medium has a laminated film as described above, and the laminated film has a base layer and a magnetic layer formed on the base layer. Usually, a soft magnetic layer, a base layer, a magnetic layer and a protective layer are sequentially formed on a substrate such as aluminum or glass to manufacture the magnetic recording medium.

[0090] [Example]

[0091] Next, the sputtering target of the present invention was produced, and the effect of the magnetic layer formed using the sputtering target was confirmed and described below. However, the description here is for illustrative purposes only and is not intended to be limiting.

[0092] Various sputtering targets are used to manufacture laminated films. Using a magnetron sputtering device (C-3010 manufactured by Canon anelva), films are formed on a glass substrate in the order of Cr-Ti (6nm), Ni-6W (5nm), and Ru ("LowP-Ru" refers to Ru sputtered under low pressure (1Pa), and "HighP-Ru" refers to Ru sputtered under high pressure (10Pa). The film thickness of both is 10nm, and the total film thickness is 20nm.) Then, the sputtering targets shown in Table 1 are sputtered at 300W in an Ar3.0Pa atmosphere to form a magnetic film with a film thickness of 11nm, and then a Ru (3nm) film is formed as a protective film (OC) to prevent oxidation, thereby forming each layer. Here, Figure 1 The magnetic layer represented by "Mag" is formed using sputtering targets of different compositions as shown in Table 1. The metal component of each sputtering target is the same, and the metal component contains 27 at% Pt in the form of CoPt alloy. As a metal oxide component, although Examples 1 to 3 contain NbO2, Comparative Examples 1 and 2 do not contain NbO2. It should be noted that the volume ratio of the oxide is calculated by estimating the volume of the entire sputtering target and the volume of the oxide based on the density and weight of the raw material powder, and by their ratio. In this way, the volume ratio of the oxide can be calculated based on the raw material powder.

[0093] For the laminated films of each example and comparative example, the coercive force Hc and the magnetic cluster (or magnetic domain) size Dn, which is an index of high magnetic separability of magnetic particles, were measured. The measurement methods were as follows.

[0094] For the manufactured laminated film, a polar Kerr device (BH-810MS) manufactured by Neoark was used to apply an external magnetic field (H) in a direction perpendicular to the film and measure the Kerr rotation angle (θ) to produce a hysteresis curve. The maximum applied magnetic field was ±20 kOe, and the magnetic field scanning speed was 0.5 kOe / second. The obtained hysteresis curve (Major hysteresis curve) was analyzed and the coercive force Hc was calculated.

[0095] Next, once the applied magnetic field reaches 20kOe, sweep the magnetic field to -Hc, and then sweep the applied magnetic field to 20kOe again to obtain the minor hysteresis curve. Next, find dθ / dH by differentiating the major loop and the minor loop. Reset the horizontal axis to the effective magnetic field (Heff) converted using the calculation formula.

[0096] Effective magnetic field (Heff) = H - demagnetization field Hd

[0097] When dθ / dH obtained from the main loop and dθ / dH obtained from the secondary loop are plotted with the effective magnetic field as the horizontal axis, the curves overlap at the position where dθ / dH increases, thereby determining the value Hd of the demagnetization field.

[0098] Next, the saturation magnetization Ms was measured using a sample vibration type magnetometer (VSM) manufactured by Tamagawa Corporation.

[0099] The demagnetization field coefficient Nd is calculated by the following formula.

[0100] Demagnetization field coefficient Nd = Hd / (4πMs)

[0101] The magnetic cluster size Dn is calculated by the following formula using the calculated Nd and the film thickness t of the magnetic film of the sample.

[0102] Magnetic cluster size Dn = t × (1-Nd 2 ) 1 / 2 / Nd

[0103]

Table 1

[0104]

[0105] As shown in Table 1, in Examples 1 to 3 containing NbO2, relatively high coercivity Hc and relatively low magnetic cluster size Dn can be obtained, and the magnetic separation between magnetic particles can be improved while maintaining high coercivity. In contrast, in Comparative Examples 1 and 2 not containing NbO2, although other components are roughly the same, they are inferior in coercivity Hc and magnetic cluster size Dn.

[0106] In addition, regarding Example 3, Figure 2 The measurement results of the target XRD are shown in . The XRD analysis conditions are as follows.

[0107] The measurement method when analyzing the sputtering target with an X-ray diffractometer (Rigaku Ultima IV) can be based on JIS K0131: 1996, and the measurement conditions can be set as follows.

[0108] Sputtering target analysis position: Cutting surface perpendicular to the sputtering surface

[0109] X-ray source: Cu-Kα

[0110] Tube voltage: 40kV

[0111] Tube current: 30mA

[0112] Divergence slit: 1°

[0113] Divergence longitudinal limiting slit: 10mm

[0114] Scattering slit: 8mm

[0115] Light receiving slit: open

[0116] Goniometer: Sample horizontal type

[0117] Scanning speed: 10° / min

[0118] Scanning step: 0.01°

[0119] Measuring range (2θ): 20°~80°

[0120] Background removal: Fitting method (Specifically, a simple peak search is performed, and after removing the peak part, a polynomial is fitted to the remaining data. Background removal is performed based on X-ray analysis software (manufactured by Rigaku Co., Ltd., comprehensive powder X-ray analysis software PDXL2))

[0121] It should be noted that the analysis position was ground with #2000 water-resistant abrasive paper, and then polished with a slurry in which aluminum oxide abrasive particles with a particle size of 0.3 μm were dispersed, and the flat and slightly uneven surface in the analysis position was measured. It should be noted that "flat and slightly uneven surface" is not a strict standard, but only means avoiding the part when there are uneven surfaces that hinder the analysis.

[0122] The obtained XRD pattern was analyzed using X-ray analysis software (manufactured by Rigaku Co., Ltd., comprehensive powder X-ray analysis software PDXL2). Figure 2 It can be seen that a diffraction peak can be observed near 2θ=30.27°±1°. By comparing the position of the observed diffraction peak with the data of the position of the diffraction peak of CoNb2O6 in JCPDS card No.01-072-0482, it can be confirmed that the position of the observed peak corresponds to the position of the main peak (2θ=30.27°) of JCPDS card No.01-072-0482. In other words, it can be confirmed that there is a phase containing Co, Nb and O. It should be noted that although Figure 2 No diffraction peak corresponding to NbO 2 was observed, but this is considered to be because, as described above, almost all of the NbO 2 in the raw material reacted with the metal component and / or oxide during the sintering process.

Claims

1. A sputtering target, in, Contains Co and Pt as metal components, and NbO 2 As metal oxide components.

2. The sputtering target according to claim 1, in, NbO 2 The content is 0.5mol%~30mol%.

3. A sputtering target comprising Co and Pt as metal components and having a phase containing three elements of Co, Nb and O.

4. The sputtering target according to claim 3, in, When measured using an X-ray diffractometer, a diffraction peak was observed at 2θ=30.27°±1°.

5. The sputtering target according to claim 4, in, When measured under the following conditions, a diffraction peak was observed at 2θ=30.27°±1°: (1) The analysis position of the sputtering target is the cross section perpendicular to the sputtering surface; (2) Using Cu-Kα as the X-ray source; (3) The tube voltage is 40 kV; (4) The tube current is 30mA; (5) The divergence slit is 1°; (6) The divergence longitudinal limiting slit is 10 mm; (7) The scattering slit is 8 mm; (8) The light receiving slit is in an open state; (9) The goniometer uses a horizontal specimen type; (10) Scanning speed is 10° / min; (11) The scanning step is 0.01°; (12) The measurement range is 2θ = 20° to 80°; (13) Background removal using fitting method; (14) The analysis position is ground using #2000 water-resistant abrasive paper, and then polished using a slurry in which aluminum oxide abrasive particles with a particle size of 0.3 μm are dispersed; (15) The flat surface with little unevenness in the analysis position is measured.

6. The sputtering target according to any one of claims 1 to 5, in, As a metal oxide component, it also contains TiO 2 、SiO 2 Cr 2 O 3 , B 2 O 3 , CoO and Co 3 O 4 At least one metal oxide in the sputtering target, the total content of the metal oxide in the sputtering target is 20vol% to 60vol%.

7. The sputtering target according to any one of claims 1 to 6, in, The content of Pt is 2 mol% to 25 mol%.

8. A method for producing a laminated film, include: On the base layer containing Ru, a magnetic layer is formed by sputtering using the sputtering target according to any one of claims 1 to 7.

9. A laminated film comprising: a base layer containing Ru, a magnetic layer formed on the base layer and containing Co and Pt as metal components; the magnetic layer containing NbO 2 As metal oxide components.

10. The laminated film according to claim 9, in, The magnetic layer further contains TiO as a metal oxide component. 2 、SiO 2 Cr 2 O 3 , B 2 O 3 , CoO and Co 3 O 4 At least one metal oxide.

11. A magnetic recording medium comprising the laminated film according to claim 9 or 10.

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