Patterned heat absorbing layers for granular storage media

Abstract

This application discloses a patterned heat-absorbing layer for granular storage media. A heat-assisted magnetic recording device includes a granular magnetic recording layer and a heat-absorbing layer formed on top of the magnetic recording layer. The heat-absorbing layer is patterned to include rows extending in the transtrack direction of the magnetic medium, each adjacent pair of the row being separated from each other by an insulating material.

Description

Background Art

[0001] In a patterned media device, the magnetic material on the disk is patterned or grown into small isolated islands or "grains" so that there is only a single magnetic domain in each island or grain. Each single magnetic domain can be a single grain or multiple strongly coupled grains that switch magnetic states in unison as a single magnetic volume. This is in contrast to conventional non-patterned media, where a single "bit" can have multiple magnetic grains separated by grain boundaries. The media can be manufactured so that there is no magnetic material in the areas between the islands.

[0002] Although patterned media are preferentially viewed as a promising tool for effectively delaying the superparamagnetic limit (areal density limit where thermal fluctuations in the media spontaneously change the polarization of the recorded bit), currently favored techniques for creating patterned media tend to cause damage to the magnetic islands, resulting in inconsistencies in properties such as coercivity distribution, switching field distribution, or deviations in Curie temperature between grains. This damage to the magnetic islands tends to increase with increasing pattern density. Therefore, conventional patterning methods are not conducive to the formation of high-density patterns. Summary of the invention

[0003] According to one implementation, a magnetic medium includes a granular recording layer and a heat absorbing layer formed on top of the magnetic recording layer. The heat absorbing layer is patterned to include rows extending in a cross-track direction of the magnetic medium, and each adjacent pair of the rows is separated from each other by an insulating material.

[0004] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description in a simplified form. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other features, details, utilities, and advantages of the claimed subject matter will become apparent from the following more particular written detailed description of various implementations as further illustrated in the accompanying drawings and defined in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 An example data storage device including a magnetic medium having a patterned heat absorbing layer is shown.

[0006] Figure 2 A cross-sectional view of another example magnetic media having a patterned heat absorbing layer is shown.

[0007] Figure 3 A cross-sectional view of yet another example magnetic media having a patterned heat absorbing layer is shown.

[0008] Figure 4A cross-sectional view of yet another example magnetic media having a patterned heat absorbing layer is shown.

[0009] Figure 5 A cross-sectional view of yet another example magnetic media having a patterned heat absorbing layer is shown.

[0010] Figure 6 Patterning of a magnetic medium with thermal absorption patterned in two perpendicular directions is shown.

[0011] Figure 7 A view of yet another example magnetic media having a patterned heat absorbing layer is shown. DETAILED DESCRIPTION

[0012] Currently popular techniques for making granular recording layers in magnetic media tend to produce magnetic grains that lack uniformity in magnetic properties, such as coercivity distribution, switching field distribution, and Curie temperature. It is well known that these grain-to-grain inconsistencies can lead to an increase in write errors and a decrease in the achievable signal-to-noise ratio (SNR). At the same time, it is known that this decrease can be reversed and potentially overcome by improving the head / media thermal gradient.

[0013] As used herein, "head / media thermal gradient" refers to the thermal gradient observed in a heat-assisted magnetic recording (HAMR) device that exists between (1) a data bit on the media currently being heated and undergoing a write transition and (2) an immediately adjacent data bit that had passed under the write element immediately prior to the current write transition.

[0014] The current state of heat-assisted magnetic recording (HAMR) shows that the currently achievable SNR values ​​are well below the theoretical limit that can be supported for a given grain size. It is theoretically believed that if the head / medium thermal gradient is sufficiently increased compared to the head / medium thermal gradient observed in existing granular media devices, the SNR can be increased to the highest theoretically achievable SNR value. This increase in SNR will allow the grain size to be reduced, thereby increasing the media areal density. For example, the current thermal gradient in a HAMR device is approximately 7-9K / nm. If this thermal gradient is increased to a value greater than about 30K / nm, the media areal density can be increased by 50-100%.

[0015] According to one implementation, the technology disclosed herein provides a patterned heat absorbing layer formed on top of a granular magnetic recording layer in a HAMR device. The patterned heat absorbing layer can significantly improve the SNR of the device by increasing the effective thermal gradient, thereby mitigating the performance-degrading effects of inconsistent inter-grain properties.

[0016] Figure 1An example data storage device 100 is shown that includes a magnetic medium 108 having a patterned heat absorbing layer 140 (see view B) formed on top of a granular magnetic recording layer 132. The granular magnetic recording layer 132 includes a plurality of magnetic grains separated from each other by non-magnetic material. During a recording process, data can be recorded in the magnetic medium by selectively switching the polarity of the magnetic grains in the magnetic recording layer 132 using a magnetic write pole (not shown) on a transducer head assembly 120. As shown in view A, the magnetic medium 108 rotates about a spindle center or disk rotation axis 112 and includes an inner diameter 104 and an outer diameter 102 between which are a plurality of concentric data tracks.

[0017] The transducer head assembly 120 is mounted on the actuator assembly 109 at one end distal to the actuator rotation axis 114. The transducer head assembly 120 flies in close proximity above the surface of the magnetic media 108 during disk rotation. During a seek operation, the actuator assembly 109 rotates about the actuator rotation axis 114. The seek operation positions the transducer head assembly 120 over a target data track for read and write operations.

[0018] In a HAMR device, magnetic grains on the magnetic medium 108 are temporarily heated during the recording process to selectively reduce the magnetic coercivity in tightly focused areas that substantially correspond to individual data bits. For example, light from a heat source (not shown) can be directed into a waveguide (not shown) and focused to a bit location on the magnetic medium 108 via a near field transducer (NFT) 152 as the bit location is affected by the magnetism generated by the write pole. The heated area is then encoded with the recorded data bit based on the polarity of the applied magnetic write field. After cooling, the magnetic coercivity substantially returns to its pre-heating level, thereby stabilizing the magnetization of the data bit. The writing process is repeated for multiple data bits on the storage medium, and such data bits can be read using a magnetoresistive read head.

[0019] Figure 1 The cross-sectional view of the magnetic medium 108 shown in view B of FIG. 1 includes a layer stack 124, which in different implementations may include various different layers formed on top of a substrate, such as described below with respect to FIG. Figure 2Those exemplary layers described. The granular magnetic recording layer 132 is formed on top of the layer stack 124 and includes magnetic islands or grains (e.g., grains 134) positioned at fixed locations separated from each other by non-magnetic material (e.g., non-magnetic material 136). In different implementations, the magnetic grains can be formed by any of a variety of different processes including a subtractive process (e.g., a process that creates magnetic islands by milling or etching into a magnetic layer and then backfilling with non-magnetic material), or alternatively by one or more additive processes (e.g., a process that creates magnetic islands by nucleating magnetic grains at growth points on a seed layer). Depending on the method used to create the granular magnetic recording layer 132, the magnetic islands can be shaped and arranged according to a selected pattern, or alternatively, can be randomly or semi-randomly shaped and arranged.

[0020] A patterned heat absorbing layer 140 is formed on top of the granular magnetic recording layer 132, and a capping layer 142 (e.g., a carbon capping layer or other protective layer) is formed on top of the patterned heat absorbing layer 140. Depending on the manufacturing process used, the capping layer 142 may or may not be patterned to match the pattern of the patterned heat absorbing layer 140. In one implementation, Figure 1 The patterned structure shown in view B of FIG. 1 is formed by depositing the material of the patterned heat absorbing layer 140 on top of the granular magnetic recording layer 132; depositing the cap layer 142 on the patterned heat absorbing layer 140; and etching through both the patterned heat absorbing layer 140 and the cap layer 142 to create gaps (e.g., gaps 144) in the material of the patterned heat absorbing layer 140. Various other fabrication processes may be used in other implementations, some of which are described herein with respect to the following Figure 2-Figure 7 Have a discussion.

[0021] In some implementations, the memory device 100 uses gaps (e.g., gaps 144) between islands of the patterned heat absorbing layer 140 to indicate the boundaries of data bits (e.g., groups of dies that switch together to maintain a single data bit). Figure 1 , a single data bit 150 is defined beneath an island of patterned heat absorbing layer 140 between gap 144 and gap 152.

[0022] The gaps (e.g., gaps 144, gaps 152) in the patterned heat absorbing layer 140 are filled with an insulating material (e.g., air or other insulator) that is used to prevent lateral diffusion of heat between adjacent grains in the granular recording layer. This is shown in view B via arrows indicating that the heat flow downward from the NFT 152 is directed downward toward the grains directly below, which together define a single data bit 150. The insulating material in the gaps of the patterned heat absorbing layer 140 prevents this heat from diffusing laterally in the down-track direction to other adjacent data bits, such as data bit 148. As a result, a large thermal gradient is observed between adjacent data bits 148 and 150. In one implementation, this observed thermal gradient is approximately 15-20 degrees Kelvin scale per nanometer, while an otherwise identical HAMR device and medium lacking the patterned heat absorbing layer 140 can provide a gradient of approximately 9 degrees K per nanometer. This increased thermal gradient has the effect of improving the SNR of the medium and reducing the write error rate, thereby allowing a potentially significant corresponding increase in areal recording density.

[0023] In one implementation, the patterned heat absorbing layer 140 includes a thermally conductive metal or metal alloy having an extinction value (k) of at least 0.8. The value of the extinction coefficient may be greater than the extinction value (k) of the capping layer 142. For example, the patterned heat absorbing layer 140 may have an extinction value (k) of at least 0.8, while the capping layer 142 has a k value in the range of 0.5 to 0.6. Although the thermal conductivity of the patterned heat absorbing layer 140 may vary from implementation to implementation, in one implementation, the thermal conductivity is equal to or greater than the thermal conductivity of the granular magnetic recording layer 132. Typically, the thermal conduction across each gap (e.g., gap 144) in the patterned heat absorbing layer 140 is significantly lower than the thermal conduction within each island patterned within the layer.

[0024] In the illustrated implementation, the controller 106 of the storage device 100 is configured to control a writer (not shown) to generate magnetic transitions in the granular recording layer 132 of the magnetic medium 108 to store data. In general, it should be understood that Figure 1 The controller 106 may include software stored on a tangible computer-readable storage medium. As used herein, the term "tangible computer-readable storage medium" does not include transient propagating signals (e.g., carrier waves), but includes physically manufactured media (memory devices) including, but not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CDROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible medium that can be used to store the desired information and can be accessed by a mobile device or computer.

[0025] Figure 2A cross-sectional view of another example storage medium 200 is shown having a heat absorbing layer 204 patterned to improve the head / medium thermal gradient. Figure 2 The properties of a well-described magnetic medium can be assumed to be similar to those of Figure 1 Or the features described in other implementations disclosed herein are the same or similar.

[0026] The storage medium 200 includes a granular magnetic recording layer 202 formed on top of a layer stack 206. In different implementations, the layer stack 206 can differ in composition and purpose. In the illustrated implementation, the layer stack includes a substrate 208, which can include any substrate material, such as ceramic glass, amorphous glass, aluminum, etc. An adhesive layer 210 is disposed between the substrate 208 and a heat sink layer 212, and the heat sink layer 212 is formed on the adhesive layer 210 to promote adhesion between the substrate 208 and the heat sink layer 212 by reducing the likelihood of the substrate 208 delaminating from the rest of the layer structure.

[0027] The heat spreader layer 212 includes a metal or a metal alloy and may include one or more materials such as Ag, Cu, Au, Al, Cr, Mo, W, etc. In some implementations, the heat spreader layer 212 is grown on the substrate 208 in a specific orientation to help promote directional growth of subsequently formed layers in the stack.

[0028] The seed layer 214 is deposited on the heat sink layer 212 and is used to control the amount or rate of heat that is conducted away from the granular magnetic recording layer 202 and into the underlying heat sink layer. In various implementations, the seed layer may also be used for other additional functions, such as preventing interdiffusion between adjacent layers and / or for orienting and / or controlling the grain size of magnetic grains included in the granular magnetic recording layer 202.

[0029] The granular magnetic recording layer 202 includes magnetic grains (e.g., magnetic grains 242) and a magnetic spacer (e.g., spacer material 244) that separates the magnetic grains from each other. The non-magnetic spacer may include one or more of crystalline ZrO2 and an amorphous spacer (e.g., C, SiO2, Al2O3, Si3N4, TiO2, WO3, Ta2O5, BN, or another alternative oxide, nitride, boride, or carbide material). Suitable materials for the magnetic grains include, for example, FePt, FeXPt alloys, FeXPd alloys, and Co3Pt. The granular magnetic recording layer 202 may have a thickness ranging from about 5 nanometers to about 30 nanometers.

[0030] The heat absorbing layer 204 is formed on top of the granular magnetic recording layer 202 and includes a thermally conductive material, preferably a thermally conductive material that is as thermally conductive as or more thermally conductive than the granular magnetic recording layer 202. The heat absorbing layer 204 is patterned via any suitable process, such as milling or selective etching, to include alternating gaps (e.g., gaps 216) and islands (e.g., islands 218) in the down-track direction of the media 200. In one implementation, this is achieved by patterning the material of the heat absorbing layer 204 into rows that extend in the cross-track direction of the media, such as Figure 1 The specific pattern employed in the heat absorbing layer 204 (eg, the size and shape of the islands) may vary from implementation to implementation.

[0031] exist Figure 2 , each island (e.g., island 218, island 240, island 246) in the heat absorbing layer 204 has a down-track width that corresponds to a group of underlying magnetic grains that together form a single data bit (e.g., grains that switch as a single unit to store a single data bit). Each gap in the heat absorbing layer 204 is positioned to be substantially aligned with a boundary between two data bits on the storage medium 200. For example, island 218 covers a group of grains that switch together to store a first data bit 222; island 240 covers a group of grains that switch together to store a second data bit; and island 246 covers a group of grains that switch together to store a third data bit 230. It is worth noting that there may not be a precise vertical alignment between the gaps 216, gaps 226 in the patterned heat absorbing layer 204 and the boundaries between individual grains in the granular magnetic recording layer 202. However, gaps 216, 226 in patterned heat absorbing layer 204 can be used to time individual write transitions of the storage device so that any grain having a majority of its magnetic domain beneath a particular island among islands 218, 240, 246, etc., is converted to a portion of a data bit that is generally located beneath that island.

[0032] During nominal storage device operation, the storage medium 200 rotates on an axis beneath a write element that includes an NFT 234 that focuses heat on the storage medium 200. During a write operation to an individual data track on the medium, a device controller (not shown) controls the write element to perform write transitions to a sequence of data bits arranged continuously along the track. These transitions are precisely timed by the storage device controller so that each data bit in the sequence is located beneath a different island in the islands (across track rows) of the heat absorbing layer 204.

[0033] Various considerations may drive the relative sizes of the islands and gaps in the heat absorbing layer 204. Generally, larger islands (e.g., islands 240) provide better heat absorption and more efficiently heat the underlying granular magnetic recording layer 202. However, if the gaps between the islands of the patterned heat absorbing layer 204 are too small, a greater amount of heat may flow across the gaps. Additionally, if the gaps are so large that individual magnetic grains in the granular magnetic recording layer 202 reside between the gaps, these stray grains may negatively impact device performance. By way of example and not limitation, a suitable gap-to-island duty cycle may be in the range of about 1 / 9 (meaning that the islands have about 9 times the down-track width of the gaps) to 1 / 1 (meaning that the islands and gaps have approximately equal down-track widths).

[0034] In the implementation shown, the gaps in the heat absorbing layer 204 are filled with air, which serves to laterally insulate adjacent data bits from each other in the granular recording medium. In other implementations, the gaps may be filled with another insulating material.

[0035] A capping layer 236 is formed on top of the heat absorbing layer 204. The capping layer 236 is used to seal and protect the heat absorbing layer from corrosion and provide a smooth continuous surface that can slide under the read / write head. In one implementation, the capping layer 236 includes diamond-like carbon or silicon nitride (SiN). In some implementations, the capping layer 236 may also include a lubricant layer.

[0036] exist Figure 2 , NFT 234 is shown as heating the underlying data bits 224. The material in islands 240 of heat absorbing layer 204 concentrates this heat on data bits 224, and gaps 216 and gaps 226 laterally contain the spread of heat within the cross-section of heat absorbing layer 204 in the down-track direction of storage medium 200, effectively increasing the thermal gradient during writing.

[0037] Figure 3 A cross-sectional view of yet another example magnetic medium 300 having a patterned heat absorbing layer 308 is shown. Figure 3 The characteristics of the magnetic media explicitly described can be assumed to be the same or similar to the characteristics described in other implementations disclosed herein. The magnetic medium 300 includes a layer stack 306 and a granular magnetic recording layer 302 formed on top of the layer stack 306. The granular magnetic recording layer 302 includes a plurality of magnetic islands separated from each other by non-magnetic material. In one implementation, the magnetic islands are generally aligned in rows extending in a cross-track direction of the magnetic medium 300 (e.g., into the page). A patterned heat absorbing layer 308 is formed on top of the granular magnetic recording layer 302. A capping layer 310 (e.g., a carbon capping layer) is formed on top of the patterned heat absorbing layer 308.

[0038] and Figure 2 In contrast, Figure 3 The magnetic medium 300 includes material of a capping layer 310 deposited in gaps (e.g., gaps 312) between islands of a patterned heat absorbing layer 308. In one implementation, the patterned heat absorbing layer 308 and the capping layer 310 are formed by: (1) depositing material of the patterned heat absorbing layer 308 on top of the granular magnetic recording layer 302; (2) selectively etching through the deposited material to form gaps (e.g., gaps 312); and (3) depositing material of the capping layer 310 on top of the patterned heat absorbing layer 308 and within the gaps.

[0039] Figure 3 The design shown provides Figure 2 308. The granular magnetic recording layer 302 is completely encapsulated by the cover layer. Therefore, the granular magnetic recording layer 302 is protected from potential corrosion. This corrosion protection can be achieved at the expense of a small loss of thermal gradient due to the possibility of some small amount of heat conduction through the cover layer 310 within the gaps of the patterned heat absorbing layer 308. In addition to the above, Figure 3 The design may be Figure 2 The design is easier to create mechanically, partly due to the shallower etching depth and due to the Figure 3 In the design of FIG. 3 , the potentially hard (eg, carbon or the like) material of the capping layer 310 is not subjected to etching.

[0040] Figure 4 A cross-sectional view of yet another example storage medium 400 is shown having a patterned heat absorbing layer 404. The patterned heat absorbing layer 404 is formed on top of a granular magnetic recording layer 402, which is formed on a layer stack 406. Figure 4 Design and Figure 2 and Figure 3 The difference is that the gaps (eg, gaps 412) in the patterned heat absorbing layer 404 are filled with a thermal isolation material 414, which may include any suitable dielectric, such as silicon oxide, various nitrides, and the like.

[0041] After filling the gaps with the thermal isolation material 414, the capping layer 410 is formed to extend continuously across the surface of the medium 400, forming a reliable plane. In this implementation, the granular magnetic layer 402 is fully encapsulated, and the inclusion of thermal isolation material in the gaps of the patterned heat absorbing layer 404 ensures that the thermal isolation material is not too large. Figure 3 Better (higher) head / medium thermal gradient in the design, Figure 3 In the design of the cover layer 410, the material (e.g., carbon-based or the like) is deposited in the gaps of the patterned heat absorbing layer 404. Figure 4 Features of the storage medium 400 explicitly described may be assumed to be the same or similar to features described in other implementations disclosed herein.

[0042] Figure 5 A cross-sectional view of yet another example storage medium 500 is shown having a patterned heat absorbing layer 504. The patterned heat absorbing layer 504 is formed on top of a granular magnetic recording layer 502, which is formed on a layer stack 506. Figure 5 Design and Figure 2 and Figure 3 The difference is that the gaps (e.g., gaps 512) in the patterned heat absorbing layer 504 are partially (but not completely) filled with thermal isolation material 514. For example, this design can be created by depositing the material of the patterned heat absorbing layer 504 and the cover layer 510, etching through both the patterned heat absorbing layer 504 and the cover layer 510, and then backfilling selective areas of the storage medium 500 with thermal isolation material 514.

[0043] No relative to Figure 5 Features of the storage medium 500 explicitly described may be assumed to be the same or similar to features described in other implementations disclosed herein.

[0044] Figure 6 6 shows the patterning of yet another example patterned heat absorbing layer 604 on the magnetic medium 600. Figure 1 Similar to view C of FIG. 6 , the patterned heat absorbing layer 604 is patterned to include rows extending in the cross-track (radial) direction of the magnetic medium 600 (eg, radial direction rows indicated by arrows 610 ). However, Figure 6 The patterned heat absorbing layer 604 is additionally patterned to include columns extending in the down-track direction (e.g., the down-track direction columns indicated by arrows 612), thereby effectively dividing the material of the patterned heat absorbing layer 604 into rectangular islands 618, 620, etc. According to one implementation, each of the rectangular islands 618, 620, etc. has a radial width corresponding to (equal to or substantially equal to) the width of each data track defined on the magnetic medium 600. This design is advantageous because it mitigates a phenomenon known as "thermal blooming," according to which heat from an NFT (not shown) is absorbed by multiple data tracks, thereby potentially increasing noise, read errors, and / or corrupting data. Here, the bidirectional patterning of the patterned heat absorbing layer 604 provides cross-track isolation, ensuring that heat is not easily transferred between data bits on directly adjacent data tracks (e.g., there is thermal isolation between Track 1 and Track 2).

[0045] As with other implementations described herein, the patterned heat absorbing layer 604 can be formed on top of a granular magnetic recording layer (not shown) that includes magnetic grains. In one implementation, the controller of the storage device uses the boundaries between the islands of the patterned heat absorbing layer 604 to time write transitions so that different data bits are effectively defined by the magnetic grains that are generally located underneath each of the islands of the patterned heat absorbing layer 604. In practice, each data bit on the magnetic medium 600 has a size and location corresponding to one of the rectangular islands of the patterned heat absorbing layer 604. That is, the magnetic grains under the first island 618 store data for a first data bit, the magnetic grains under the second island 620 store data for a second data bit, and so on.

[0046] and Figure 1 Compared to the pattern shown in (View C), Figure 6 One disadvantage of the pattern shown in is that the corresponding device controller may need to implement bidirectional write synchronization to ensure that write transitions are performed when the write element is centered along each island in the cross-track direction and in the down-track direction. Figure 1 The pattern shown in can be implemented using unidirectional write synchronization (eg, clocking the transitions at each island passed in the down-track direction without regard for cross-track positioning).

[0047] Figure 7 The formation stages 702, 704 and 706 of another example patterned heat absorbing layer 708 formed on a granular magnetic recording layer 710 are shown. The method for creating the patterned heat absorbing layer 708 is advantageous because it limits cross-track thermal blooming without requiring bidirectional write synchronization. In this implementation, the patterned heat absorbing layer 708 acts as an absorbing layer (e.g., relative to the Figure 1-Figure 6 ) and an initial switching layer that facilitates magnetic switching of grains in the granular magnetic recording layer 710. Unlike other patterned heat absorbing layers disclosed herein, the patterned heat absorbing layer 708 is an alloy comprising two magnetic materials that includes an isolator such as an oxide and / or nitride. For example, the alloy can be a coupled grain / continuous (CGC) alloy. When deposited according to specific conditions, the layer epitaxially grows magnetic grains on top of existing grains of the granular magnetic recording layer 710. As shown in view 702, the isolator 712 in the top magnetic alloy phase is isolated to grain boundaries (e.g., grain boundary 712). After selectively etching areas of the granular top magnetic alloy (as shown in view 704), a carbon capping layer 726 can be deposited, as shown in view 706.

[0048] During the patterning process shown in view 704, a selective etch is performed to pattern the top alloy to pattern the layer in the down-track direction of the medium, as shown. In some implementations, the patterning can divide the patterned heat absorbing layer 708 into rows extending along the cross-track direction. Thus, the patterning of the patterned heat absorbing layer 708 increases the down-track thermal gradient by providing isolation (e.g., air) between each adjacent pair of data bits, such as the data bits under islands 718, 720.

[0049] Unlike a continuous heat absorbing layer that may lose track capability in the cross-track direction due to thermal blooming, the patterned heat absorbing layer 708 does not suffer from cross-track thermal blooming because it is granular and there is low thermal conductivity isolation at the grain boundaries in the cross-track direction, which allows for high TPI comparable to conventional HAMR media. Therefore, it is possible to achieve high TPI without performing complex 2D patterning (such as Figure 6 Reduce heat haloing in the case of

[0050] In one implementation, the patterned heat absorbing layer 708 has a Curie temperature that is higher than the Curie temperature (Tc) of the granular magnetic recording layer 710. If the recording process heats the granular magnetic recording layer 710 to a temperature that is higher than its Curie temperature but lower than the Curie temperature of the patterned heat absorbing layer 708, the patterned heat absorbing layer 708 acts as a recording assist layer. In this case, the application of a write field during the heating and recording steps causes the patterned heat absorbing layer 708 to magnetically align with the applied field ahead of the granular magnetic recording layer 710, thereby effectively assisting in aligning the grains of the granular magnetic recording layer 710 in the same direction as it cools. This provides an additional effective increase in the down-track thermal gradient.

[0051] Because the patterned heat absorbing layer 708 is magnetic, it is magnetically coupled to the granular magnetic recording layer 710 and has a magnetization that is aligned with the magnetization direction of the underlying magnetic grains. Therefore, this layer contributes to the readback signal without the losses that would otherwise exist between the read element and the top magnetic layer (e.g., as in other embodiments with a non-magnetic patterned absorbing layer).

[0052] The above description, examples and data provide a complete description of the structure and use of exemplary embodiments of the disclosed technology. Since many embodiments of the disclosed technology can be made without departing from the spirit and scope of the disclosed technology, the disclosed technology is in the claims attached below. In addition, the structural features of different embodiments can be combined in another embodiment without departing from the claims.

[0053] Further examples:

[0054] Example 1. A heat-assisted magnetic recording (HAMR) device, comprising: a magnetic medium, comprising: a magnetic recording layer, the magnetic recording layer comprising a plurality of magnetic grains separated from each other by non-magnetic material; and a heat absorbing layer, the heat absorbing layer formed on top of the magnetic recording layer, the heat absorbing layer being patterned to include rows extending in a cross-track direction of the magnetic medium, each adjacent pair of the rows being separated from each other by insulating material.

[0055] Example 2. The HAMR device as described in Example 1 is characterized in that the heat absorbing layer is further patterned into columns extending in the down-track direction of the magnetic medium, and the columns extending in the down-track direction and the rows extending in the cross-track direction divide the heat absorbing layer into rectangular islands.

[0056] Example 3. The HAMR device of Example 1, wherein the rows of the heat absorbing layer are separated from each other by rows of insulating material.

[0057] Example 4. The HAMR device of Example 2, wherein the ratio of the along-track length of the gap between each pair of rectangular islands to the along-track length of each of the islands is at least one-ninth.

[0058] Example 5. The HAMR device as described in Example 1 further includes: a read / write controller configured to control a write head to write a separate data bit on the magnetic medium by converting a group of magnetic grains to the same magnetic polarity, the separate data bit having an along-track width corresponding to the along-track width of a corresponding one of the rows of the heat absorbing layer extending in the cross-track direction.

[0059] Example 6. The HAMR device of Example 2, further comprising: a read / write controller configured to control a write head to write a separate data bit on the magnetic medium by converting a group of magnetic grains to the same magnetic polarity, the separate data bit having a size corresponding to one of the rectangular islands.

[0060] Example 7. The HAMR device of Example 1, wherein the heat absorbing layer is a granular magnetic layer.

[0061] Example 8. A system comprising: a magnetic medium comprising a heat absorbing layer formed on top of a granular magnetic recording layer, the heat absorbing layer being patterned into rows; and a controller configured to control a write element to selectively convert the magnetic polarity of a sequence of data bits arranged continuously along a data track of the magnetic medium, each adjacent pair of the rows of the heat absorbing layer being separated by an insulating region aligned along an axis having a boundary between two adjacent data bits in the sequence of data bits.

[0062] Example 9. The system of Example 8, wherein the rows extend in a cross-track direction of the medium, and the heat absorbing layer is further patterned into columns extending in a down-track direction of the magnetic medium, the columns and the rows dividing the heat absorbing layer into rectangular islands.

[0063] Example 10. The system of Example 9, wherein each of the data bits of the sequence is located under a different one of the rectangular islands.

[0064] Example 11. The system of Example 8, wherein the rows of the heat absorbing layer are separated from each other by rows of insulating material.

[0065] Example 12. The system of Example 11, wherein the ratio of the along-track length of the gap between each pair of rectangular islands to the along-track length of each of the islands is at least one-ninth.

[0066] Example 13. The system of Example 8, wherein the heat absorbing layer is a granular magnetic layer. Example 14. The system of Example 8, wherein the insulating region between each pair in the row is adapted to increase the thermal gradient between opposing pairs of data bits in the sequence.

[0067] Example 15. A method comprising: controlling a write element to selectively switch the magnetic polarity of a sequence of continuous data bits aligned along a data track of a magnetic medium, the magnetic medium comprising a heat absorbing layer patterned into rows on top of a granular magnetic recording layer, each adjacent pair in the rows of the heat absorbing layer being separated by an insulating region aligned along an axis having a boundary between two adjacent data bits in the sequence.

[0068] Example 16. The method of Example 15, wherein the rows extend in a cross-track direction of the medium, and the heat absorbing layer is further patterned into columns extending in a down-track direction of the magnetic medium, the columns and the rows dividing the heat absorbing layer into rectangular islands.

[0069] Example 17. The method of Example 16, wherein each of the data bits of the sequence is located under a different one of the rectangular islands.

[0070] Example 18. The method of Example 16, wherein controlling the write element further comprises: executing logic to ensure single-dimensional write synchronization.

[0071] Example 19. The method of Example 16, wherein controlling the write element further comprises: executing logic to ensure dual-dimensional write synchronization.

[0072] Example 20. The method of Example 16, wherein the insulating region between each pair in the row is adapted to increase a thermal gradient between opposing pairs of data bits in the sequence.

Claims

1. A heat-assisted magnetic recording (HAMR) device, comprising: Magnetic media, including: a magnetic recording layer including a plurality of magnetic grains separated from each other by a nonmagnetic material; and A patterned heat absorbing layer is formed on top of the magnetic recording layer, the patterned heat absorbing layer being patterned to include rows extending in a cross-track direction of the magnetic medium, each adjacent pair of the rows being separated from each other by an insulating material.

2. The heat-assisted magnetic recording (HAMR) device according to claim 1, wherein: The patterned heat absorbing layer is further patterned into columns extending in a down-track direction of the magnetic medium, and the columns extending in the down-track direction and the rows extending in the cross-track direction divide the patterned heat absorbing layer into rectangular islands.

3. The heat-assisted magnetic recording (HAMR) device of claim 1, wherein: The rows of the patterned heat absorbing layer are separated from each other by rows of insulating material.

4. The heat-assisted magnetic recording (HAMR) device according to claim 2, wherein: The ratio of the along-track length of the gap between each pair of rectangular islands to the along-track length of each of the islands is at least one-ninth.

5. The heat-assisted magnetic recording (HAMR) device of claim 1, further comprising: a read / write controller configured to control a write head to write individual data bits on the magnetic medium by converting a group of magnetic grains into the same magnetic polarity, the individual data bits having an along-track width corresponding to an along-track width of a corresponding one of the rows of the patterned heat absorbing layer extending in the cross-track direction.

6. The heat-assisted magnetic recording (HAMR) device of claim 2, further comprising: A read / write controller is configured to control a write head to write an individual data bit on the magnetic medium by converting a group of magnetic grains to the same magnetic polarity, the individual data bit having a size corresponding to one of the rectangular islands.

7. The heat-assisted magnetic recording (HAMR) device of claim 1, wherein: The patterned heat absorbing layer is a granular magnetic layer.

8. A system comprising: a magnetic medium comprising a patterned heat absorbing layer formed on top of a granular magnetic recording layer, the patterned heat absorbing layer being patterned into rows; as well as A controller is configured to control the write element to selectively switch the magnetic polarity of a sequence of data bits arranged continuously along a data track of the magnetic medium, each adjacent pair of the rows of the patterned heat absorbing layer being separated by an insulating region aligned along an axis having a boundary between two adjacent data bits in the sequence of data bits.

9. The system according to claim 8, characterized in that The rows extend in a cross-track direction of the medium, and the patterned heat absorbing layer is further patterned into columns extending in a down-track direction of the magnetic medium, the columns and the rows dividing the patterned heat absorbing layer into rectangular islands.

10. The system according to claim 9, characterized in that Each of the data bits of the sequence is located beneath a different one of the rectangular islands.

11. The system according to claim 8, characterized in that The rows of the patterned heat absorbing layer are separated from each other by rows of insulating material.

12. The system according to claim 11, characterized in that The ratio of the along-track length of the gap between each pair of rectangular islands to the along-track length of each of the islands is at least one-ninth.

13. The system of claim 8, wherein: The patterned heat absorbing layer is a granular magnetic layer.

14. The system of claim 8, wherein: The insulating region between each pair in the rows is adapted to increase the thermal gradient between opposing pairs of data bits in the sequence.

15. A method comprising: A write element is controlled to selectively switch the magnetic polarity of a sequence of continuous data bits aligned along a data track of a magnetic medium, the magnetic medium comprising a patterned heat absorbing layer patterned into rows on top of a granular magnetic recording layer, each adjacent pair in the rows of the patterned heat absorbing layer being separated by an insulating region aligned along an axis having a boundary between two adjacent data bits in the sequence.

16. The method according to claim 15, characterized in that The rows extend in a cross-track direction of the medium, and the patterned heat absorbing layer is further patterned into columns extending in a down-track direction of the magnetic medium, the columns and the rows dividing the patterned heat absorbing layer into rectangular islands.

17. The method according to claim 16, characterized in that Each of the data bits of the sequence is located beneath a different one of the rectangular islands.

18. The method according to claim 16, characterized in that Controlling the writing element further comprises: Implement logic to ensure single-dimension write synchronization.

19. The method according to claim 16, characterized in that Controlling the writing element further comprises: Logic is implemented to ensure synchronization of dual-dimensional writes.

20. The method of claim 16, wherein: The insulating region between each pair in the rows is adapted to increase the thermal gradient between opposing pairs of data bits in the sequence.

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