Magnetic recording medium with small recording grain size and high aspect ratio and manufacturing method thereof

Abstract

Various apparatus, systems, methods, and media are disclosed to provide a thermally assisted magnetic recording (HAMR) media having a small recording grain size with a high aspect ratio. An example magnetic recording medium includes: a substrate; the radiating fin layer is positioned on the substrate; the cushion layer comprises MgO (magnesium oxide)-TiO (titanium oxide) and is positioned on the radiating fin layer; the interface layer comprises TiN and is positioned on the cushion layer; a first nucleation layer on the interfacial layer and comprising FePt-Ag-X, where X is an oxide; a second nucleation layer on the first nucleation layer and comprising FePt-Ag-Y, where Y is an oxide or a nitride; and a magnetic recording layer on the second nucleating layer. In another example, the TiN is formed as part of the cushion layer rather than in the interface layer.

Description

Technical Field

[0001] In some respects, this disclosure relates to magnetic recording media. More specifically, but not exclusively, this disclosure relates to magnetic recording media with small recording grain size and high aspect ratio, and methods for manufacturing such media. Background Technology

[0002] Magnetic storage systems, such as hard disk drives (HDDs), are used in a variety of devices in both static and mobile computing environments. Examples of devices incorporating magnetic storage systems include data center servers, desktop computers, laptop computers, portable hard disk drives, high-definition television (HDTV) receivers, set-top boxes, video game controllers, and portable media players.

[0003] A typical disk drive includes magnetic storage media in the form of one or more platters. A disk is typically formed from a few main materials: a substrate material that gives it structure and rigidity, a magnetic recording layer that holds the magnetic pulses or moments that store digital data, and a media protector layer and a lubricant layer to protect the magnetic recording layer. A typical disk drive also includes a read head and a write head, typically in the form of magnetic transducers that sense and / or change the magnetic moments stored on the recording layer of the disk.

[0004] Heat-assisted magnetic recording (HAMR) systems can increase the areal density of information recorded magnetically on various magnetic media. To achieve higher areal densities for magnetic storage, smaller magnetic grain sizes, such as less than 6 nanometers (nm), may be required. In HAMR, high temperatures are applied to the medium during writing to facilitate recording to small magnetic grains. These high temperatures can be achieved using a near-field transducer with a laser diode coupled to a slider within the HAMR disk drive. Despite the benefits of HAMR, further improvements in areal density are needed. One approach to addressing this goal is to further reduce the size of the magnetic recording grains within the medium. Aspects of this disclosure aim to address this challenge. Summary of the Invention

[0005] The following is a brief overview of some aspects of this disclosure to provide a basic understanding of these aspects. This content is not a comprehensive overview of all contemplated features of this disclosure, nor is it intended to identify key or essential elements of all aspects of this disclosure, nor to depict the scope of any or all aspects of this disclosure. Its sole purpose is to present various concepts of some aspects of this disclosure in a simplified form as a prelude to the more detailed description that follows.

[0006] In one aspect, this disclosure provides a magnetic recording medium comprising: a substrate; a heat sink layer disposed on the substrate; a pad layer comprising MgO-TiO disposed on the heat sink layer; an interface layer comprising TiN disposed on the pad layer; a first nucleation layer disposed on the interface layer and comprising FePt-Ag-X, wherein X is an oxide; a second nucleation layer disposed on the first nucleation layer and comprising FePt-Ag-Y, wherein Y is an oxide or a nitride; and a magnetic recording layer disposed on the second nucleation layer.

[0007] In one aspect, this disclosure provides a magnetic recording medium comprising: a substrate; a heat sink layer disposed on the substrate; a pad layer disposed on the heat sink layer and comprising MgO-TiO(MTO) and TiN; a first nucleation layer disposed on the pad layer and comprising FePt-Ag-X, wherein X is an oxide; a second nucleation layer disposed on the first nucleation layer and comprising FePt-Ag-Y, wherein Y is an oxide or a nitride; and a magnetic recording layer disposed on the second nucleation layer, wherein the pad layer comprises a first surface and a second surface closer to the first nucleation layer than the first surface; and wherein the concentration of TiN in the pad layer is higher at the second surface than at the first surface.

[0008] In one aspect, this disclosure provides a method for manufacturing a magnetic recording medium, the method comprising: providing a substrate; providing a heat sink layer on the substrate; providing a pad layer on the heat sink layer, the pad layer comprising MgO-TiO (MTO); sputtering a first nucleation layer on the pad layer using an N2 deposition gas, the first nucleation layer comprising FePt-Ag-X, wherein X is an oxide, wherein the N2 from the N2 deposition gas and the Ti from the MTO of the pad layer form TiN; sputtering a second nucleation layer on the first nucleation layer, the second nucleation layer comprising FePt-Ag-Y, wherein Y is an oxide or a nitride; and providing a magnetic recording layer on the second nucleation layer.

[0009] In one aspect, this disclosure provides a magnetic recording medium formed using a process comprising the following steps: providing a substrate; providing a heat sink layer on the substrate; providing a pad layer on the heat sink layer, the pad layer comprising MgO-TiO (MTO); sputtering a first nucleation layer on the pad layer using an N2 deposition gas, the first nucleation layer comprising FePt-Ag-X, wherein X is an oxide, wherein the N2 from the N2 deposition gas and the Ti from the MTO of the pad layer form TiN; sputtering a second nucleation layer on the first nucleation layer, the second nucleation layer comprising FePt-Ag-Y, wherein Y is an oxide or nitride; and providing a magnetic recording layer on the second nucleation layer. Attached Figure Description

[0010] The following description includes more specific aspects illustrated with reference to the accompanying drawings. It should be understood that these drawings depict only certain aspects of this disclosure and should therefore not be considered as limiting its scope, which is described and explained with additional specificity and detail by means of the drawings.

[0011] Figure 1 This is a top schematic diagram of an exemplary data storage device configured for heat-assisted magnetic recording (HAMR) according to aspects of this disclosure. The exemplary data storage device includes a slider and an HAMR medium comprising small magnetic recording dies with a high aspect ratio.

[0012] Figure 2 Based on the aspects of this disclosure Figure 1 A side view of an exemplary slider and HAMR medium.

[0013] Figure 3 This is a side view schematic diagram of an exemplary HAMR medium according to aspects of this disclosure, which includes, in addition to other layers, a pad layer and a first nucleation layer and a second nucleation layer, which together provide a basis for small magnetic recording grains with high aspect ratio in the magnetic recording layer.

[0014] Figure 4a It is a cross-sectional view of the comparative magnetic media, which includes a bar chart of the magnetic recording grain size / diameter of the comparative magnetic media.

[0015] Figure 4b It is a cross-sectional view of an exemplary magnetic medium according to aspects of this disclosure, which includes a histogram of the magnetic recording grain size / diameter of the exemplary magnetic medium.

[0016] Figure 4c This is an example of aspects according to this disclosure. Figure 4b Exemplary magnetic media and Figure 4a A table comparing various media characterization parameters of magnetic media.

[0017] Figure 5 Examples Figure 4a Multiple cross-sectional views of magnetic recording grains of comparative magnetic media at various resolutions or sections show undesirable characteristics such as short grains or defective grains.

[0018] Figure 6 Examples of aspects according to this disclosure are illustrated. Figure 4b Multiple cross-sectional views of the magnetic recording grains of the exemplary magnetic medium at various resolutions or sections, which show the desired characteristics, such as uniform grains with small diameters.

[0019] Figure 7Several cross-sectional views of exemplary magnetic recording media according to aspects of this disclosure are illustrated, showing the concentrations of selected material elements contained therein.

[0020] Figure 8 This is a flowchart of an exemplary process for manufacturing a HAMR medium comprising small magnetic recording grains with a high aspect ratio, according to aspects of this disclosure.

[0021] Figure 9 This is a flowchart of another exemplary process for manufacturing a HAMR medium comprising small magnetic recording grains with a high aspect ratio, according to aspects of this disclosure. Detailed Implementation

[0022] In the following detailed description, reference is made to the accompanying drawings, which form part of this detailed description. In addition to the exemplary aspects, aspects, and features described above, other aspects, aspects, and features will become apparent from the accompanying drawings and the following detailed description. The description of elements in each figure is referential to elements in the preceding figures. The same numbers may refer to the same elements in the figures, including alternative aspects of the same elements.

[0023] In some aspects, this disclosure relates to various apparatuses, systems, methods, and media for providing magnetic recording media, such as heat-assisted magnetic recording (HAMR) media, which, among other characteristics, can provide optimized or at least improved magnetic properties within the HAMR medium. It should be noted that HAMR is a type of energy-assisted magnetic recording (EAMR), and is a broad term encompassing both HAMR and microwave-assisted magnetic recording (MAMR). At least some aspects of this disclosure are not limited to HAMR and are applicable to EAMR.

[0024] As mentioned above, further improving the areal density of magnetic storage is a challenge. One way to address this goal is to further reduce the size of the magnetic recording grains within the medium. As used herein, "grain size" refers to the diameter of columnar magnetic recording grains formed in one or more magnetic recording layers of a magnetic medium. Aspects of this disclosure relate to designing magnetic recording media with smaller magnetic recording grains having a high aspect ratio (e.g., the ratio of grain height to grain diameter). In one aspect, a magnetic recording medium is provided having a pad layer comprising MgO-TiO (MTO); and a first nucleation layer and a second nucleation layer that serve as templates for a subsequent magnetic recording layer (MRL) having small magnetic recording grains with a high aspect ratio. The first nucleation layer may be made of FePt-Ag oxide and deposited on the MTO pad layer using a nitrogen (N2) deposition gas sputtering. The N2 may react with and / or combine with Ti from the pad layer to form TiN (e.g., an interface layer made of TiN). The second nucleation layer can be made of FePt-Ag oxide / nitride and is deposited on the first nucleation layer using argon (Ar) deposition gas sputtering. One or more magnetic recording layers are disposed on top of the second nucleation layer. The resulting magnetic medium exhibits excellent performance characteristics, including smaller grain diameters compared to comparative recording media (e.g., a reduction of approximately 17%). More specifically, the grain diameter is reduced by approximately 17%, and the aspect ratio is increased by approximately 14.7%. As a result, the areal density is expected to increase accordingly.

[0025] Exemplary Examples and Implementation Schemes

[0026] Figure 1 This is a top schematic diagram of an exemplary data storage device configured for heat-assisted magnetic recording (HAMR) according to aspects of this disclosure. The exemplary data storage device includes a slider and an HAMR medium comprising small magnetic recording dies with a high aspect ratio. A laser ( Figure 1 Not visible in the text, but can be seen in the references. Figure 2Positioned using a head / slider 108, 114) the disk drive 100 may include one or more disks / media 102 for storing data. The disks / media 102 reside on a spindle assembly 104, which is mounted to a drive housing 106. Data may be stored along tracks in the magnetic recording layer of the disk 102. Reading and writing of data are accomplished using a head 108 (slider), which may have both read and write elements (108a and 108b). The write element 108a is used to change the properties of the magnetic recording layer of the disk 102 and thus write information to it. In one aspect, the head 108 may have magnetoresistive (MR) based elements, such as a tunneling magnetoresistive (TMR) element for reading and write poles with coils energized for writing. In operation, a spindle motor (not shown) rotates the spindle assembly 104, and thus the disk 102, to position the head 108 at a specific location along the desired disk track 107. The position of the magnetic head 108 relative to the disk 102 can be controlled by a control circuit system 110 (e.g., a microcontroller). It should be noted that although an exemplary HAMR system is shown, at least some aspects of this disclosure can be used in other HAMR or EAMR magnetic data recording systems or non-HAMR or non-EAMR magnetic data recording systems, including shingled write magnetic recording (SMR) media, perpendicular magnetic recording (PMR) media, or microwave-assisted magnetic recording (MAMR) media.

[0027] Figure 2 yes Figure 1 A side view schematic diagram of the slider 108 and the magnetic recording medium 102. The magnetic recording medium 102 includes magnetic recording layers (these layers are in...) Figure 2 Not visible in the text, but see [link / reference] Figure 3 and Figure 6 The slider 108 may include a sub-base 112 attached to the top surface of the slider 108. The laser 114 may be attached to the sub-base 112 and possibly to the slider 108. The slider 108 includes a writing element (e.g., a writer) 108a and a reading element (e.g., a reader) 108b, positioned along the air bearing surface (ABS) 108c of the slider, for writing information to and reading information from the medium 102, respectively. In other aspects, the slider may also include a layer of Si or a Si cladding 120. This layer is optional.

[0028] In operation, laser 114 is configured to generate and direct light energy into a waveguide (e.g., along the dashed line) in the slider, which directs the light to a near-field transducer (NFT) 122 near the air bearing surface (e.g., the bottom surface) 108c of the slider 108. Upon receiving light from laser 114 via the waveguide, NFT 122 generates localized heat that heats a portion of the medium 102 within or near both the write element 108a and read element 108b. Recording temperatures are expected to be in the range of approximately 350°C to 400°C. Figure 2 In the illustrated aspect, the laser-directed light is positioned within the writer 108a and near the trailing edge of the slider. In other aspects, the laser-directed light can be positioned between the writer 108a and the reader 108b. Figure 1 and Figure 2 A specific example of an HAMR system is shown. In other examples, the magnetic recording medium 102 can be used in other suitable HAMR systems (e.g., with additional sliders configured for HAMR).

[0029] Figure 3 This is a side view schematic diagram 300 of an exemplary HAMR medium according to aspects of this disclosure, which includes, in addition to other layers, a pad layer and a first nucleation layer and a second nucleation layer, which together provide a basis for small magnetic recording grains with high aspect ratio in the magnetic recording layer. Figure 3The HAMR dielectric 300 has a stacked structure comprising a substrate 302 at a bottom / base layer, a soft pad layer (SUL) 304 on the substrate 302, a seed layer 306 for a heat sink layer on the SUL 304, a heat sink layer 308 (e.g., made of Cr) on the seed layer 306, a heat barrier layer 310 (e.g., RuAl-TiO2) on the heat barrier layer 308, a pad layer 312 (e.g., MgO-TiO or MTO) on the heat barrier layer 310, a first nucleation layer (“M0-1”) 314 (e.g., a FePt-Ag oxide layer deposited using N2 gas sputtering) on ​​the pad layer 312, and a second nucleation layer (“M0”) on the first nucleation layer 314. -2”) 316 (e.g., FePt-Ag-oxide layer deposited using Ar gas sputtering), a first magnetic recording layer (“M1”) 318 (e.g., FePt-X, where X is a suitable segregant) on the second nucleation layer 316, a second magnetic recording layer (“M2”) 320 (e.g., FePt-X, where X is a suitable segregant) on the first magnetic recording layer 318, a third magnetic recording layer (“M3”) 322 (e.g., FePt-X, where X is a suitable segregant) on the second magnetic recording layer 320, a capping layer 324 (e.g., CoFe or CoPt and one or more segregants) on the third MRL 322, an outer coating layer 326 (e.g., made of diamond-like carbon (DLC) or other suitable material) on the capping layer 324, and a lubricant layer 328 on the outer coating layer 326. In one aspect, each of the first nucleating layer 314, the second nucleating layer 316, and the MRL 318 (322) can be collectively referred to as the MRL structure 330.

[0030] In some aspects, the HAMR medium 300 may include additional layers. In one example, the HAMR medium 300 also includes an adhesion layer (which may be formed, for example, from NiTa, CrTi, etc.) located on the substrate 302 and under the SUL 304. The adhesion layer can be used to reduce delamination of layers or films deposited above the adhesion layer.

[0031] The dielectric 300 can be fabricated using one or more material deposition techniques for each layer deposited on the substrate 302. In one aspect, the pad layer 312, as well as the first nucleation layer (314) and the second nucleation layer (316), may be of particular interest. More specifically, using MTO for the pad layer 312 may have advantages over other pad or seed layer materials such as MgO. That is, pads made of MgO may require complex and excessively time-consuming deposition processes, such as radio frequency (RF) sputtering. On the other hand, and more specifically, due to the improved conductivity of MTO (compared to MgO), the use of MTO allows for the use of direct current (DC) sputtering, which is faster and more efficient than RF sputtering. Therefore, the use of MTO provides manufacturing efficiency. At the same time, Ti from MTO can sometimes migrate to other layers (such as MRL or elsewhere) and cause problems with recording performance (e.g., reduced recording performance). The applicant has discovered that the use of N2 gas (e.g., pure or substantially pure N2 (e.g., with no more than 5% impurities)) during the sputtering deposition of the first nucleation layer (M0-1) 314 leads to the formation of TiN, which appears to provide several beneficial performance results in the medium. These performance results (with smaller grains and high aspect ratios) have been briefly described above and will be described in more detail below.

[0032] In one aspect, TiN tends to form / concentrate at the top surface of the MTO pad 312. For example, the pad 312 includes a first surface (e.g., the bottom surface) and a second surface (e.g., the top surface) that is closer to the first nucleation layer 314 than the first surface, and the concentration of TiN in the pad 312 is higher at the second surface than at the first surface. In another aspect, TiN can even be efficiently formed as... Figure 3 The TiN layer 332 (e.g., an interface layer made of TiN) is shown between the pad layer 312 and the first nucleation layer 314. Alternatively, TiN may be formed / concentrated at or near the bottom surface of the first nucleation layer 314. In either case, the resulting dielectric structure exhibits an improved grain structure compared to a comparative dielectric structure, thereby providing or expected to provide improved magnetic recording performance.

[0033] As described above, the first nucleation layer 314 may be made of FePt-Ag-X, where X is an oxide. Suitable oxides include SiO2, TiO2, Cr2O3, ZrO2, Al2O3, Fe2O3, Ta2O5, etc. In one example, X is SiO2. In one aspect, the first nucleation layer 314 may include a certain amount of embedded N2 sputtered from the layer. In one aspect, the first nucleation layer (Mo-1) 314 composition is 34Fe-34Pt-10.5Ag-21.5(SiO2) (mol%). Ag may be in the range of 0.1 mol% to 15 mol%, and SiO2 may be in the range of 0.5 mol% to 21.5 mol%.

[0034] The second nucleation layer 316 may be made of FePt-Ag-Y, where Y is an oxide or nitride. Suitable Y oxides include SiO2, TiO2, Cr2O3, ZrO2, Al2O3, Fe2O3, Ta2O5, etc. Suitable Y nitrides include Si3N4, TiN, CrN, TaN, ZrN, VN, etc. In one example, Y is SiO2. The use of oxides or nitrides in the second nucleation layer (Mo-2) 316 is considered to contribute to small recording grains in the MRL (318, 320, 322) of the dielectric structure. In one aspect, the FePt in the second nucleation layer (Mo-2) 316 ranges from 15 mol% to 45 mol%. In another aspect, the oxides and / or nitrides in the second nucleation layer (Mo-2) 316 range from 0.5 vol% to 70 vol%. In one aspect, the Ag in the second nucleation layer (M0-2) 316 has a content ranging from 0.1 mol% to 12 mol%. In another aspect, the second nucleation layer 316 may be made of FePt-10.5Ag-21.5SiO2, or with slight deviations from these percentages (e.g., a deviation of 5% to 10%). In another aspect, for example, the second nucleation layer 316 may be made of 34Fe-34Pt-10.5Ag-21.5(SiO2) (mol%). Ag may be in the range of 0.1 mol% to 15 mol%, and SiO2 may be in the range of 0.5 mol% to 21.5 mol%.

[0035] In some examples, substrate 302 has an outer diameter (i.e., OD) of approximately 97 mm and a thickness of approximately 0.5 mm. In other examples, the OD may be 95 mm or 95.1 mm. (Generally speaking, such disks are referred to as "3.5-inch" disks). In some aspects, substrate 302 may be made of one or more materials, such as Al alloys, NiP-coated Al, glass, glass ceramics, and / or combinations thereof.

[0036] In some aspects, SUL 304 may be made of one or more materials, such as Co, Fe, Mo, Ta, Nb, B, Cr, or other soft magnetic materials, or combinations thereof. SUL 304 may comprise an amorphous compound with one or more of Mo, Nb, Ta, W, and B added, or a combination of Co and Fe (e.g., a CoFe alloy). SUL 304 may be configured to support magnetization of the magnetic recording layer structure (e.g., layers 314 to 322 or layers 318 to 322 only) during data storage operations. More specifically, SUL 304 may be configured to provide a return path to the magnetic field applied during write operations.

[0037] In some respects, the heat sink seed layer 306 serves as a growth template for the subsequently deposited film (including the heat sink layer 308). Functional objectives of the (heat sink) seed layer 306 include small grain size and good crystallographic texture, both of which are desirable for good dielectric recording performance. In one respect, the heat sink seed layer 306 is made of RuAl or other suitable materials known in the art.

[0038] In some respects, the heat sink layer 308 may be made of one or more materials such as Cr (as shown) or Ag, Al, Au, Cu, Mo, Ru, W, CuZr, MoCu, AgPd, CrRu, CrV, CrW, CrMo, CrNd, NiAl, NiTa, combinations thereof, and / or other suitable materials known in the art.

[0039] In some aspects, the thermal barrier layer 310 may be deposited directly on the heat sink layer 308 to provide thermal resistance to the heat sink layer and / or to provide a thermal gradient in the medium, thereby facilitating writing to the medium. The thermal barrier layer 310 may be etched to reduce roughness. In one aspect, the thermal barrier layer 310 may be made of RuAl-TiO2 and / or other suitable materials known in the art.

[0040] In some aspects, a pad 312 is provided as a pad or seed layer for nucleation layers 314 and 316 and for the MRL (318 to 322) to aid nucleation, thereby allowing appropriate crystal growth within the MRL so that the MRL will have a good crystal structure with small grains. As mentioned above, the pad 312 can be made of MgO-TiO (MTO). In one aspect, the pad can be implemented using multiple layers (e.g., multiple MTO layers or a combination of MgO layers and MTO layers).

[0041] Suitable materials for the first and second nucleation layers are as described above.

[0042] As shown in the figure, the MRL structure 330 includes five magnetic recording layers (314 (M0-1), 316 (M0-2), 318 (M1), 320 (M2), and 322 (M3)). In some aspects, the M1 to M3 sublayers of the MRL structure 330 may be made of FePt or an alloy selected from FePtX, where X is a material selected from oxides Cu, Ni, and combinations thereof. In some aspects, these sublayers of the MRL structure 330 may be made of a CoPt alloy. In some examples, the sublayers of the MRL structure 330 may include one or more of L10 FePt, FePd, CoPt, or MnAl, or may include a CoPt / CoPd multilayer alloy, each layer having a predetermined thickness, granular structure, small grain size, desired uniformity, high coercivity, high magnetic flux, and good atomic ordering, which is suitable for HAMR media. Other additive elements may be added to the above-described MRL structure 330, including, for example, Ag, Au, Cu, or Ni. In other embodiments, different numbers of MRLs may be present in the MRL structure 330, instead of five MRLs. In one aspect, M1 is made of FePtAgCu(BN), M2 is made of FePt(BN)C, and M3 is made of FePt(BN)(SiO2).

[0043] In some aspects, the capping layer 324 may be made of Co, CoPt, CoFe, or CoPd. In one example, the capping layer 324 may be a bilayer structure having layers comprising Co or Pt / Pd. In some embodiments, the capping layer 324 may be made of specific combinations of materials (e.g., Co / Pt, Co / Au, Co / Ag, Co / Al, Co / Cu, Co / Ir, Co / Mo, Co / Ni, Co / Os, Co / Ru, Co / Ti, Co / V, Fe / Ag, Fe / Au, Fe / Cu, Fe / Mo, Fe / Pd, Ni / Au, Ni / Cu, Ni / Mo, Ni / Pd, Ni / Re, etc.). In other examples, the multilayer layer material includes any combination of Pt and Pd (e.g., an alloy) or any of the following elements, alone or in combination: Au, Ag, Al, Cu, Ir, Mo, Ni, Os, Ru, Ti, V, Fe, Re, etc.

[0044] In some aspects, the outer coating 320 may be made of carbon (e.g., diamond-like carbon or DLC). In another aspect, the lubricant layer 322 may be made of a polymer-based lubricant.

[0045] It should be noted that, as used herein, the terms "above," "below," "on," and "between" refer to the relative position of one layer with respect to other layers. Therefore, a layer deposited or disposed on, above, or below another layer may be in direct contact with that layer, or may have one or more intermediate layers. Furthermore, a layer deposited or disposed between layers may be in direct contact with the layers, or may have one or more intermediate layers.

[0046] With respect to the processes described herein, these processes may, in some cases, perform sequences of actions in different orders. In other cases, the process may skip one or more actions. In still other cases, one or more actions are performed simultaneously. In some cases, additional actions may be performed. Unless otherwise specified, various deposition processes or subprocesses may be used to perform the deposition of at least some of these layers, including but not limited to physical vapor deposition (PVD), sputtering deposition and ion beam deposition, plasma-enhanced chemical vapor deposition (PECVD) and other forms of chemical vapor deposition (CVD), low-pressure chemical vapor deposition (LPCVD), and atomic layer chemical vapor deposition (ALCVD). In other cases, other suitable deposition techniques known in the art may also be used.

[0047] Figure 4a This is a cross-sectional view of the comparative magnetic medium 400, including a histogram 402 showing the magnetic recording grain size / diameter of the comparative magnetic medium. This cross-sectional view was produced using transmission electron microscopy (TEM) and shows a 50 nm × 50 nm region of the magnetic recording medium 400. The comparative magnetic medium 400 has a... Figure 3 The medium has a similar structure, except that M0-1, M0-2, and M1 are replaced by FePt-SiO2, FePt-Ag, and FePt-X (where X is an oxide such as SiO2), respectively. Histogram 402 shows a bimodal grain distribution for the comparative magnetic medium 400, where instead of the advantage of a single grain size (e.g., similar to a uniform grain size), there are two peaks representing different grain sizes, one much larger than the other. This bimodal grain distribution is undesirable because it does not indicate a uniform grain size distribution, and subsequent analysis of experimental data will show a negative impact on magnetic recording performance.

[0048] Figure 4b This is a cross-sectional view of an exemplary magnetic medium 404 according to aspects of this disclosure, including a histogram 406 showing the magnetic recording grain size / diameter of the exemplary magnetic medium. This cross-sectional view was produced using TEM and shows a region of the magnetic recording medium 404 measuring 50 nm × 50 nm. The exemplary magnetic medium 404 has a... Figure 3The media have the same structure, but with specific choices of some variable materials, such that MO-1 (314) is made of FePt-SiO2, MO-2 (316) is made of FePt-SiO2, and M1 (318) is made of FePt-X (where X is AgCu(BN)). In one aspect, for example, Figure 4a The first nucleation layer (M0-1) composition is 34Fe-34Pt-10.5Ag-21.5(SiO2) (mol%), and Figure 4a The second nucleation layer (M0-2) composition is 34Fe-34Pt-10.5Ag-21.5(SiO2) (mol%). In one aspect, M1 is made of FePtAgCu(BN), M2 is made of FePt(BN)C, and M3 is made of FePt(BN)(SiO2). Histogram 406 illustrates the uniform grain distribution of the exemplary magnetic medium 404, which has the advantage of a single grain size, resulting in a single peak. This uniform grain distribution is desirable because subsequent analysis of experimental data will show a positive impact on magnetic recording performance.

[0049] Figure 4c This is an example of aspects according to this disclosure. Figure 4b Exemplary magnetic media and Figure 4a Table 408 compares various characterization parameters of the comparative magnetic media. These characterization parameters include μ0Hc (coercivity), S* (degree of hysteresis or slope of the magnetic ring), μ0Hn (nucleation field or field strength required to reverse grain magnetization), SFD (dispersion of the magnetic field required to reverse the magnetization direction of FePt grains), grain size (diameter) in nm, spacing (PD, distance from one grain center to the center of an adjacent grain) in nm, fill fraction (grain area compared to the total area of ​​the layer) in percentage, and height (h or grain height) in nm. The “sd” parameter is the standard deviation of the corresponding value.

[0050] A key finding from Table 408 is the reduction in grain size (diameter), which is significant for... Figure 4b The example magnetic medium 404 has a wavelength of 5.93 nm, while for... Figure 4a The comparison medium 400 has a diameter of 7.13 nm. Therefore, compared to the comparison medium 400, the grain diameter in the exemplary medium 404 is reduced by approximately 17%, and the aspect ratio (height divided by diameter) is increased by approximately 14.7%.

[0051] Figure 5 Examples Figure 4aMultiple cross-sectional images 500 of magnetic recording grains of a comparative magnetic medium at various resolutions or sections show undesirable characteristics such as short grains or defective grains. Specifically, short grains 502, which can lead to a bimodal grain distribution, are shown in the lower right image. Additionally, defective grains 504 with inverted phase are shown in the lower right image. In one aspect, TEM is used to produce... Figure 5 Cross-sectional view of the image.

[0052] Figure 6 Examples of aspects according to this disclosure are illustrated. Figure 4b Multiple cross-sectional views of the magnetic recording grains of an exemplary magnetic medium at various resolutions or sections illustrate desired properties, such as uniform grains with small diameters. Figure 6 As shown, the magnetic recording grains are well-defined, homogeneous, and without... Figure 5 The diagram illustrates the types of short or defective grains used to compare magnetic media. In one aspect, TEM is used to generate... Figure 6 Cross-sectional view of the image.

[0053] Figure 7 Several cross-sectional views of exemplary magnetic recording media according to aspects of this disclosure are illustrated, showing the concentrations of selected material elements contained therein. For example, image / view 702 shows an exemplary magnetic recording medium (e.g., Figure 3 , Figure 4b and Figure 6 Images 702, 706, and 708 show concentrated regions of N in an exemplary magnetic recording medium, with lighter colors indicating the locations of N. For example, image / view 704 shows a concentrated region of Si in an exemplary magnetic recording medium, with lighter colors indicating the locations of Si. Image / view 706 shows concentrated regions of Mg and Ti in an exemplary magnetic recording medium (note that white lines have been superimposed on the image to show the concentrated regions of each of Mg and Ti). Image / view 708 shows concentrated regions of Fe, Pt, and Cr in an exemplary magnetic recording medium (note that white lines have been superimposed on the image to show the concentrated regions of each of Cr, FePt grains, and Pt concentrated in the top region of the grains). Image / view 710 shows a concentrated region of O in an exemplary magnetic recording medium, with lighter colors indicating the locations of O. As can be seen from images 702, 706, and 708, N and Ti are effectively concentrated in the region directly below the grains. As discussed above, TiN can be formed at or near the top surface of the MTO pad during Mo-1 deposition, and these images 702 and 706 confirm this observation.

[0054] Figure 8This is a flowchart 800 of an exemplary process for manufacturing a HAMR medium comprising small magnetic recording grains with a high aspect ratio, according to an aspect of the present disclosure. In one aspect, process 800 can be used to manufacture any of the HAMR media described above, including, for example, HAMR media 102, 300, 404, and 600.

[0055] At block 802, the process provides a substrate (e.g., 302). At block 804, the process deposits a soft magnetic pad layer (SUL, e.g., 304) on the substrate. At block 806, the process deposits a seed layer (e.g., 306) on the SUL for a subsequent heat sink layer. At block 808, the process deposits a heat sink layer (e.g., 308) on the seed layer for the heat sink layer. At block 810, the process deposits a thermal barrier layer (e.g., 310) on the heat sink layer.

[0056] At box 812, the process deposits a pad layer (e.g., 312 and made of MTO) on the thermal barrier layer. At box 814, the process deposits a first nucleation layer (e.g., 314 and made of FePt-Ag oxide) on the pad layer using N2 sputtering gas. At box 816, the process deposits a second nucleation layer (e.g., 316 and made of FePt-Ag oxide / nitride) on the first nucleation layer using Ar gas. At box 818, the process deposits one or more magnetic recording layers (MRLs, e.g., 318, 320, 322 and made of FePt-X) on the second nucleation layer. In one aspect, at box 818, the process deposits exactly three MRLs (MRLs, e.g., 318, 320, 322 and made of FePt-X). At box 820, the process deposits a capping layer (e.g., 324) on one or more MRLs. At box 822, the process deposits an outer coating layer (e.g., 326) on the cover layer. At box 824, the process deposits a lubricant layer (e.g., 328) on the outer coating layer.

[0057] In one respect, depending on the media design and the target application, the process can avoid all the layers described in the deposition process 800.

[0058] It should be noted that, as used herein, the terms "above," "below," "on," and "between" refer to the relative position of one layer with respect to other layers. Therefore, a layer deposited or disposed on, above, or below another layer may be in direct contact with that layer, or may have one or more intermediate layers. Furthermore, a layer deposited or disposed between layers may be in direct contact with the layers, or may have one or more intermediate layers.

[0059] With respect to the processes described herein, these processes may, in some cases, perform sequences of actions in a different order. In other cases, the process may skip one or more actions. In still other cases, one or more actions are performed simultaneously. In some cases, additional actions may be performed. Unless otherwise specified, various deposition processes or subprocesses may be used to perform (or provide) the deposition of at least some of these layers, including but not limited to physical vapor deposition (PVD), sputtering deposition and ion beam deposition, plasma-enhanced chemical vapor deposition (PECVD) and other forms of chemical vapor deposition (CVD), low-pressure chemical vapor deposition (LPCVD), and atomic layer chemical vapor deposition (ALCVD). In other cases, other suitable deposition techniques known in the art may also be used.

[0060] Figure 9 This is a flowchart 900 of another exemplary process for manufacturing a HAMR medium comprising small magnetic recording grains with a high aspect ratio, according to an aspect of the present disclosure. In one aspect, process 900 can be used to manufacture, wholly or partially, any of the HAMR media described above, including, for example, HAMR media 102, 300, 404, and 600.

[0061] At block 902, the process provides a substrate (e.g., 302). At block 904, the process provides a heat sink layer (e.g., 308) on the substrate. At block 906, the process provides a pad layer (e.g., 312) on the heat sink layer. At block 908, the process deposits (e.g., using sputtering deposition) a first nucleation layer (e.g., 314 and made of FePt-Ag oxide) on the pad layer using N2 sputtering gas. At block 910, the process deposits (e.g., using sputtering deposition) a second nucleation layer (e.g., 316 and made of FePt-Ag oxide / nitride) on the first nucleation layer using Ar gas. At block 912, the process provides one or more magnetic recording layers (MRLs, e.g., 318, 320, 322 and made of FePt-X) on the second nucleation layer. In one aspect, at box 912, the process provides exactly three MRLs (MRLs, e.g., 318, 320, 322, and made of FePt-X).

[0062] In one aspect, the process further provides a cover layer (e.g., 324) on one or more MRLs. In another aspect, the process further provides an outer coating layer (e.g., 326) on the cover layer. In another aspect, the method further provides a lubricant layer (e.g., 328) on the outer coating layer.

[0063] Regarding various layers (such as) Figure 3 , Figure 4b , Figure 4c and Figures 6 to 9Sputtering deposition of the first nucleation layer (M0-1) and without being bound by any particular theory, the inventors have found that nitrogen (N2) gas is less effective than other sputtering deposition gases (such as argon (Ar)) and is therefore generally not used for sputtering magnetic recording layers of HAMR media. When sputtering magnetic recording layers with N2 gas, nitrides may form undesirably. More specifically, during sputtering, the N2 sputtering gas reacts with the Fe element in the FePt hard magnetic material to form FeN with soft magnetic properties. Soft magnetic materials cannot be used in hard magnetic recording layers to maintain magnetization along the easy magnetization axis to record "1" or "0". When this occurs, the highly anisotropic FePt L10 structure of the recording layer (e.g., the medium configured for HAMR) will be destroyed, resulting in reduced magnetic anisotropy and deteriorated magnetic recording performance. Therefore, digital information cannot be properly stored in the magnetic recording layer. Experimental results have confirmed that the recording performance of the medium is reduced when one or more FePt magnetic recording layers are deposited using N2 sputtering deposition gas. However, as discussed above, the inventors unexpectedly discovered that when N2 sputtering deposition gas (e.g., pure or substantially pure N2) is used to deposit the first nucleation layer (e.g., on an MTO pad), the resulting magnetic medium exhibits improved performance characteristics, indicating that the recording performance of the medium will also be improved. N2 can react with and / or combine with Ti from the seed layer to form TiN (e.g., an interface layer made of TiN). The improved performance characteristics include smaller grain diameters compared to comparative recording media (e.g., a reduction of approximately 17%). More specifically, the grain diameter is reduced by approximately 17%, and the aspect ratio increases by approximately 14.7%. As a result, the areal density is expected to increase accordingly.

[0064] It should be noted that, as used herein, the terms "above," "below," "on," and "between" refer to the relative position of one layer with respect to other layers. Therefore, a layer deposited or disposed on, above, or below another layer may be in direct contact with that layer, or may have one or more intermediate layers. Furthermore, a layer deposited or disposed between layers may be in direct contact with the layers, or may have one or more intermediate layers.

[0065] With respect to the processes described herein, these processes may, in some cases, perform sequences of actions in a different order. In other cases, the process may skip one or more actions. In still other cases, one or more actions are performed simultaneously. In some cases, additional actions may be performed. Unless otherwise specified, various deposition processes or subprocesses may be used to perform (or provide) the deposition of at least some of these layers, including but not limited to physical vapor deposition (PVD), sputtering deposition and ion beam deposition, plasma-enhanced chemical vapor deposition (PECVD) and other forms of chemical vapor deposition (CVD), low-pressure chemical vapor deposition (LPCVD), and atomic layer chemical vapor deposition (ALCVD). In other cases, other suitable deposition techniques known in the art may also be used.

[0066] Additional aspects

[0067] Examples set forth herein are provided to illustrate certain concepts of this disclosure. The apparatuses, devices, or components shown above may be configured to perform one or more of the methods, features, or steps described herein. Those skilled in the art will understand that these are merely exemplary in nature, and other examples may fall within the scope of this disclosure and the appended claims. Based on the teachings herein, those skilled in the art will understand that the aspects disclosed herein may be implemented independently of any other aspects, and two or more of these aspects may be combined in various ways. For example, any number of the aspects set forth herein may be used to implement an apparatus or to practice a method. Furthermore, in addition to or in lieu of one or more aspects set forth herein, other structures, functionalities, or structures and functionalities may be used to implement such an apparatus or to practice such a method.

[0068] The following description, with reference to schematic flowcharts and / or schematic block diagrams of methods, apparatus, systems, and computer program products according to aspects of this disclosure, describes various aspects of this disclosure. It should be understood that each block of the schematic flowcharts and / or schematic block diagrams, and combinations of blocks in the schematic flowcharts and / or schematic block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a computer or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor or other programmable data processing apparatus, create means for implementing the functions and / or actions specified in one or more blocks of the schematic flowcharts and / or schematic block diagrams.

[0069] The subject matter described herein can be implemented using hardware, software, firmware, or any combination thereof. Therefore, the terms “function,” “module,” etc., as used herein may refer to hardware, which may also include software and / or firmware components for implementing the described features. In one exemplary embodiment, the subject matter described herein can be implemented using a computer-readable medium having computer-executable instructions stored thereon, which, when executed by a computer (e.g., a processor), control the computer to perform the functionality described herein. Examples of suitable computer-readable media for implementing the subject matter described herein include non-transitory computer-readable media, such as disk storage devices, on-chip memory devices, programmable logic devices, and application-specific integrated circuits (ASICs). Furthermore, computer-readable media for implementing the subject matter described herein may reside on a single device or computing platform, or may be distributed across multiple devices or computing platforms.

[0070] It should also be noted that in some alternative implementations, the functions shown in the boxes may not occur in the order shown in the figures. For example, two boxes shown consecutively may actually be executed substantially simultaneously, or these boxes may sometimes be executed in reverse order, depending on the functionality involved. Other steps and methods that are functionally, logically, or effectically equivalent to one or more boxes or portions thereof in the figures shown can be envisioned. Although various types of arrows and lines may be used in flowcharts and / or block diagrams, it should be understood that these types of arrows and lines do not limit the scope of the corresponding aspects. For example, arrows may indicate a waiting or monitoring period of unspecified duration between the enumerated steps of the depicted aspect.

[0071] The various features and processes described above can be used independently of each other or combined in various ways. All possible combinations and sub-combinations are intended to fall within the scope of this disclosure. Furthermore, certain methods, events, states, or process blocks may be omitted in some specific implementations. The methods and processes described herein are not limited to any particular sequence, and the blocks or states associated with them may be executed in other suitable sequences. For example, the described tasks or events may be executed in a different order than specifically disclosed, or multiple tasks or events may be combined in a single block or state. Example tasks or events may be executed serially, in parallel, or in some other suitable manner. Tasks or events may be added to or removed from the disclosed exemplary aspects. The example systems and components described herein may be configured differently from those described. For example, elements may be added, removed, or rearranged compared to the disclosed exemplary aspects.

[0072] Those skilled in the art will understand that information and signals can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the foregoing specification may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0073] The term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as being more preferred or advantageous than other aspects. Similarly, the term “aspect” does not require all aspects to include the features, advantages, or modes of operation discussed. The term “coupled” is used herein to refer to direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then object A and object C can still be considered coupled to each other (even if they do not directly and physically touch each other). It should also be noted that, in the context of one component being above another component, the term “above” as used herein can be used to refer to a component that is on and / or in another component (e.g., on the surface of the component or embedded in the component). Thus, for example, a first component above a second component can refer to (1) the first component being on the second component but not in direct contact with the second component, (2) the first component being on the second component (e.g., on the surface of the second component), and / or (3) the first component being in the second component (e.g., embedded in the second component). As used herein, the terms “about 'value X'” or “approximately value X” shall refer to within 10% of 'value X'. For example, a value of about 1 or approximately 1 would mean a value in the range of 0.9–1.1. In one aspect, “about” as used herein may alternatively mean 5%. Various value ranges may be specified, described, and / or claimed in this disclosure. It should be noted that any time a range is specified, described, and / or claimed in the specification and / or claims, it refers to including the end values ​​(at least in one embodiment). In another embodiment, the range may exclude the end values ​​of the range.

[0074] As used herein, the term percentage (%) (where the unit is not specified) may be any of weight %, atomic %, mole %, mass % or volume %

[0075] While the foregoing description encompasses many specific aspects of the invention, these should not be construed as limiting the scope of the invention, but rather as examples of specific aspects. Therefore, the scope of the invention should not be determined by the aspects shown, but by the appended claims and their equivalents. Furthermore, throughout this specification, the terms "an aspect," "aspect," or similar language refer to a particular feature, structure, or characteristic described in connection with that aspect that is included in at least one aspect of this disclosure. Thus, the phrases "in one aspect," "in one respect," and similar language appearing throughout this specification may, but not necessarily all, refer to the same aspect, but rather to "one or more, but not all, aspects," unless expressly stated otherwise.

[0076] The terminology used herein is for the purpose of describing a particular implementation and is not intended to limit the implementation. As used herein, the singular forms “a / an” and “the” are also intended to include the plural forms (i.e., one or more) unless the context explicitly states otherwise. An enumerated list of items does not imply that any or all items in the list are mutually exclusive and / or mutually inclusive unless otherwise explicitly stated. It should also be understood that, unless otherwise explicitly stated, the terms “comprising,” “containing,” “including,” “having,” “comprising,” and their variations as used herein mean “including, but not limited to.” That is, these terms may specify the presence of a stated feature, integer, step, operation, element, material, or component, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, materials, components, or groups thereof. Furthermore, it should be understood that the word “or” has the same meaning as the Boolean operator “OR,” that is, it includes the possibility of “or” and “both,” and is not limited to “exclusive OR” (“XOR”), unless otherwise explicitly stated. It should also be understood that the symbol “ / ” between two adjacent words has the same meaning as “or”, unless otherwise explicitly stated. Furthermore, phrases such as “connected to,” “coupled to,” or “communicate with” are not limited to direct connections unless otherwise explicitly stated.

[0077] The various components described in this specification may be described as "comprising" or being made of certain materials or combinations of materials. In one aspect, this may mean that the component is composed of one or more specific materials. In another aspect, this may mean that the component comprises one or more specific materials.

[0078] Any reference to elements using names such as "first," "second," etc., herein does not generally limit the number or order of those elements. Rather, these designations serve as a convenient way to distinguish two or more elements or instances of elements. Therefore, references to first and second elements do not imply that only two elements can be used there, or that the first element must somehow precede the second element. Additionally, unless otherwise stated, a group of elements may include one or more elements. Furthermore, terms of the form "at least one of a, b, or c" or "a, b, c, or any combination thereof" as used in the specification or claims mean "a or b or c or any combination of these elements." For example, this term may include a, or b, or c, or a and b, or a and c, or a and b and c, or 2a, or 2b, or 2c, or 2a and b, etc.

[0079] As used herein, the term "determine" encompasses a wide range of actions. For example, "determine" can include arithmetic, calculation, processing, derivation, investigation, searching (e.g., looking in a table, database, or other data structure), probing, etc. Moreover, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), etc. Furthermore, "determine" can include parsing, selecting, choosing, building, etc.

Claims

1. A magnetic recording medium, comprising: a substrate; a heat sink layer on the substrate; a pad layer comprising MgO-TiO on the heat sink layer; an interface layer comprising TiN on the pad layer; a first nucleation layer on the interface layer and comprising FePt-Ag-X, where X is an oxide; a second nucleation layer on the first nucleation layer and comprising FePt-Ag-Y, where Y is an oxide or a nitride; and a magnetic recording layer on the second nucleation layer.

2. The magnetic recording medium of claim 1, wherein the TiN of the interface layer is formed from Ti from the pad layer and N2 during sputtering of the first nucleation layer.

3. The magnetic recording medium of claim 1, wherein Y is an oxide.

4. The magnetic recording medium of claim 3, wherein Y comprises at least one of SiO2, TiO2, Cr2O3, ZrO2, Al2O3, Fe2O3, or Ta2O5.

5. The magnetic recording medium of claim 1, wherein Y is SiO2 and X is SiO2.

6. The magnetic recording medium of claim 1, wherein Y is a nitride.

7. The magnetic recording medium of claim 6, wherein Y comprises at least one of Si3N4, TiN, CrN, TaN, ZrN, or VN.

8. The magnetic recording medium of claim 1, wherein a mole percent of Ag in the second nucleation layer is in a range of 0.1 to 12.

9. The magnetic recording medium of claim 1, wherein the first nucleation layer comprises N.

10. The magnetic recording medium of claim 1, wherein: the interface layer is directly on the pad layer; the first nucleation layer is directly on the interface layer; the second nucleation layer is directly on the first nucleation layer; and the magnetic recording layer is directly on the second nucleation layer.

11. A magnetic recording medium, comprising: a substrate; a heat sink layer on the substrate; a pad layer on the heat sink layer and comprising MgO-TiO (MTO) and TiN; a first nucleation layer on the pad layer and comprising FePt-Ag-X, where X is an oxide; a second nucleation layer on the first nucleation layer and comprising FePt-Ag-Y, where Y is an oxide or a nitride; and a magnetic recording layer on the second nucleation layer, wherein the pad layer includes a first surface and a second surface closer to the first nucleation layer than the first surface; and wherein a concentration of the TiN in the pad layer is higher at the second surface than at the first surface.

12. The magnetic recording medium of claim 11, wherein the TiN of the pad layer is formed from Ti in the MTO and N gas used during sputtering of the first nucleation layer.

13. The magnetic recording medium of claim 11, wherein Y is an oxide.

14. The magnetic recording medium of claim 13, wherein Y comprises at least one of Si02, Ti02, Cr203, Zr02, Al203, Fe203, or Ta205.

15. The magnetic recording medium of claim 11, wherein Y is Si02and X is Si02.

16. The magnetic recording medium of claim 11, wherein Y is a nitride.

17. The magnetic recording medium of claim 16, wherein Y comprises at least one of Si3N4, TiN, CrN, TaN, ZrN, or VN.

18. The magnetic recording medium of claim 11, wherein a mole percent of Ag in the second nucleation layer is in a range of 0.1 to 12.

19. The magnetic recording medium of claim 11, wherein the first nucleation layer comprises N2.

20. The magnetic recording medium of claim 11, further comprising: a thermal barrier layer directly on the heat spreader layer; wherein the cushion layer is directly on the thermal barrier layer; wherein the first nucleation layer is directly on the cushion layer; wherein the second nucleation layer is directly on the first nucleation layer; and wherein the magnetic recording layer is directly on the second nucleation layer.

21. A method for manufacturing a magnetic recording medium, the method comprising: providing a substrate; providing a heat spreader layer on the substrate; providing a cushion layer on the heat spreader layer, the cushion layer comprising MgO-TiO (MTO); sputtering a first nucleation layer on the cushion layer using a N2 deposition gas, the first nucleation layer comprising FePt-Ag-X, wherein X is an oxide, wherein N2 from the N2 deposition gas and Ti from the MTO of the cushion layer form TiN; sputtering a second nucleation layer on the first nucleation layer, the second nucleation layer comprising FePt-Ag-Y, wherein Y is an oxide or a nitride; and providing a magnetic recording layer on the second nucleation layer.

22. The method of claim 21, wherein the TiN forms a layer between the cushion layer and the first nucleation layer.

23. The method of claim 21: wherein the cushion layer comprises a first surface and a second surface closer to the first nucleation layer than the first surface; and wherein the TiN is formed such that a concentration of the TiN is higher at the second surface than at the first surface.

24. The method of claim 21, wherein Y is Si02and X is Si02.

25. The method of claim 21, wherein the second nucleation layer is sputtered using an Ar deposition gas.

26. A magnetic recording medium formed using a process, the process comprising: providing a substrate; providing a heat spreader layer on the substrate; providing a cushion layer on the heat spreader layer, the cushion layer comprising MgO-TiO (MTO); sputtering a first nucleation layer on the underlayer, the first nucleation layer comprising FePt-Ag-X, where X is an oxide, wherein N2 from the N2 deposition gas and Ti from the MTO of the underlayer form TiN; sputtering a second nucleation layer on the first nucleation layer, the second nucleation layer comprising FePt-Ag-Y, where Y is an oxide or nitride; and providing a magnetic recording layer on the second nucleation layer.

27. The magnetic recording medium formed using the process of claim 26, wherein the TiN forms a layer between the underlayer and the first nucleation layer.

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