Abstract:
Methods are disclosed for increasing areal density in Heat Assisted Magnetic Recording (HAMR) data storage systems by controlling the media layer grain size, grain size distribution, and pitch via templating techniques that are compatible with the high temperature HAMR media deposition. Embodiments include using current HAMR media seed layers as well as additionally introduced interlayers for the templating process. Topographic as well as chemical templating methods are disclosed that may employ nanoimprint technology or nanoparticle self-assembly among other patterning techniques.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to data storage devices and in particular to data storage devices employing heat assisted magnetic recording (HAMR) with very high areal data storage densities. 
       BACKGROUND 
       [0002]    Data storage devices employ rotating data storage media such as hard disk drives. In a hard disk drive, data is written to the disk medium using a write head which generates a high localized magnetic field that aligns magnetic domains within the disk in one of two directions. In some cases, the magnetization direction is up or down relative to the plane of the disk (perpendicular magnetic recording, or PMR). In other cases, the magnetization direction is within the plane of the disk. In all cases, this data may then be read-out with a read head. The write and read heads are typically integrated within a single assembly. To achieve steadily increasing data storage densities (typically measured in bits/inch), which are now at levels near 10 12  bits/in 2  (1 Tb/in 2 ), the sizes of the recording magnetic regions on the disk have been reduced to nm levels. 
         [0003]    The dimensions of magnetic grains are being steadily decreased by modifying the seed layer in order to reduce the distribution (σ D ) [where the “D” denotes diameter] of magnetic grain sizes to levels below 10 to 15% (where σ D  is a percent of the mean diameter &lt;D&gt;). Current HAMR media preferably employ a co-deposited granular L1 0  FePt—X, FePd—X, FePtAg—X, FePtAu—X, FePtCu—X, FePtNi—X, MnAl—X, etc., or L1 1  ordered CoPt—X, CoPd—X, etc. layer, where X are segregants including C, SiO x , TiO x , SiN x , BN x , B 2 O 3  and other nitrides, oxides, borides, and/or carbides. Typical percentages of the co-deposited (typically by sputtering) segregants are in the range of 15 to 50 atomic %. Depositions are done at elevated temperatures in the range 300 to 700° C. to ensure that the highly anisotropic (K u ) chemically ordered L1 0  phase is formed in a chemical ordering transition from an initially isotropic Al phase (see  FIG. 3 ).  FIG. 2  illustrates a typical HAMR media design. In the embodiments disclosed herein, it is individual magnetic grains which are patterned, where there will typically be approximately 8 to 15 grains per bit, although embodiments with approximately 4 to 10 grains per bit are also possible for higher storage densities. Thus no write synchronization is required since the magnetic grain patterning is not directly correlated with the sizes or locations of data storage bits on the medium. Since the size ranges of magnetic grains are decreased by embodiments of the invention, the signal-to-noise ratio may be improved, enabling smaller data storage bits leading to higher areal densities. 
         [0004]    Thus it would be advantageous in a data storage system to reduce the grain size distribution to levels below 10 to 15%. 
         [0005]    It is further advantageous to enable the growth of highly uniaxial perpendicular anisotropic magnetic material on a template capable of withstanding temperatures as high as 700° C. 
         [0006]    It would also be advantageous to create data storage media with small thermally stable columnar grains which are chemically distinct and isolated. 
         [0007]    It would be still more advantageous to control both the grain size and grain size distribution of FePt or other high uniaxial perpendicular anisotropy magnetic materials employed in HAMR media. 
       SUMMARY 
       [0008]    Embodiments of the present invention provide methods for improved control of the grain size and the grain size distribution by using pre-defined topographical features such as patterned surfaces to create nucleation sites for high temperature depositions of high anisotropy HAMR media. The sizes and size distributions of these features are controlled by templates used to form these features. Examples of templates include patterned media templates or monodisperse, nanoparticle arrays. By preserving the surface properties of these features, they introduce heteroepitaxial strain resulting in the high anisotropy direction aligned out-of-plane, creating nucleation sites for HAMR media (including L1 0  ordered FePt, FePd, FePtAg, FePtAu, FePtCu, FePtNi, MnAl and L1 1  ordered CoPt, CoPd) formed by subtractive processes, additive processes, or a combination of both subtractive and additive processes. 
         [0009]    A goal of some embodiments is to grow high uniaxial perpendicular anisotropic magnetic material at elevated temperatures on a patterned template, where “perpendicular” is defined as the direction away from the plane of the surface of the storage medium. 
         [0010]    A goal of some embodiments is to reduce the grain size distribution to levels below 10 to 15%. A patterned template is used to control the size and distribution of grain growth. 
         [0011]    Another goal of some embodiments is to grow grains which are chemically distinct and isolated from each other. 
         [0012]    A further goal of some embodiments is to create data storage media with small thermally stable columnar grains. 
         [0013]    A still further goal of some embodiments is to control both the grain size and grain size distribution of FePt or other high uniaxial perpendicular anisotropy magnetic materials employed in HAMR media. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a schematic diagram of a data storage system according to the present invention; 
           [0015]      FIG. 2  is a schematic side view diagram of a basic granular HAMR media design; 
           [0016]      FIG. 3  is a schematic diagram of an Al to L1 0  chemical ordering transition; 
           [0017]      FIG. 4  is a plan view TEM micrograph of a granular HAMR medium with larger grains; 
           [0018]      FIG. 5  is a plan view TEM micrograph of a granular HAMR medium with smaller grains; 
           [0019]      FIG. 6  is a side view TEM micrograph of a granular HAMR medium with larger grains; 
           [0020]      FIG. 7  is a side view TEM micrograph of a granular HAMR medium with smaller grains; 
           [0021]      FIG. 8  is a histogram of the grain size distribution for a HAMR medium with larger grains; 
           [0022]      FIG. 9  is a histogram of the grain size distribution for a HAMR medium with smaller grains; 
           [0023]      FIG. 10  is a graph of magnetization as a function of the applied magnetic field; 
           [0024]      FIG. 11  is a graph of the chemical order parameter S as a function of the grain diameter D; 
           [0025]      FIG. 12  is graph of the Curie temperature T C  as a function of the chemical order parameter S; 
           [0026]      FIG. 13  is a graph of the normalized Curie temperature as a function of the grain diameter D; 
           [0027]      FIG. 14  is schematic diagram of initial steps in a templated growth process for a HAMR storage medium with a patterned TiN seed layer; 
           [0028]      FIG. 15  is a schematic diagram of an intermediate step in a templated growth process for a HAMR storage medium with a patterned TiN seed layer; 
           [0029]      FIG. 16  is a schematic diagram of a final step in a templated growth process for a HAMR storage medium with a patterned TiN seed layer; 
           [0030]      FIG. 17  is a schematic diagram of initial steps in a templated growth process for a HAMR storage medium with a patterned metal seed layer; 
           [0031]      FIG. 18  is a schematic diagram of an intermediate step in a templated growth process for a HAMR storage medium with a patterned metal seed layer; 
           [0032]      FIG. 19  is a schematic diagram of a final step in a templated growth process for a HAMR storage medium with a patterned metal seed layer; 
           [0033]      FIG. 20  is a schematic diagram of initial steps in a hole-tone templated growth process for a HAMR storage medium; 
           [0034]      FIG. 21  is a schematic diagram of an intermediate step in a hole-tone templated growth process for a HAMR storage medium; 
           [0035]      FIG. 22  is a schematic diagram of a final step in a hole-tone templated growth process for a HAMR storage medium; 
           [0036]      FIG. 23  is a schematic diagram of an alternative final step in a hole-tone templated growth process for a HAMR storage medium; 
           [0037]      FIG. 24  is a schematic diagram of a step in a hybrid templated growth process for a HAMR storage medium; 
           [0038]      FIG. 25  is a schematic diagram of an alternative final step in the hybrid templated growth process of  FIG. 24 ; 
           [0039]      FIG. 26  is a schematic diagram of first steps in a growth process using nanoparticle arrays for generating topography for use in a templated growth process for a HAMR storage medium; 
           [0040]      FIG. 27  is a schematic diagram of further steps in the process starting in  FIG. 26 ; 
           [0041]      FIG. 28  is a schematic diagram of next steps in the process of  FIGS. 26 and 27 ; 
           [0042]      FIG. 29  is a schematic diagram of final steps in the process of  FIGS. 26-28 . 
       
    
    
     DETAILED DESCRIPTION 
       [0043]    Embodiments can provide one or more advantages over previous methods for improving areal storage densities in a HAMR data storage system. The embodiments will be described with respect to these benefits, but these embodiments are not intended to be limiting. Various modifications, alternatives, and equivalents fall within the spirit and scope of the embodiments herein and as defined in the claims. 
       Data Storage System Embodying the Present Invention 
       [0044]      FIG. 1  is a schematic diagram of a data storage system  100  embodying the present invention. System  100  includes a host computer  102 , a storage device  104 , such as a hard disk drive (HDD), and an interface  106  between the host computer  102  and the storage device  104 . Host computer  102  includes a processor  108 , a host operating system (OS)  110 , and control code  112 . The storage device or HDD  104  includes controller  114  coupled to a data channel  116 . The storage device  104  includes an arm  118  carrying a read/write head including a read element  120  and a write element  122 . 
         [0045]    In operation, host operating system  110  in host computer  102  sends commands to storage device  104 . In response to these commands, storage device  104  performs requested functions such as reading, writing, and erasing data on disk  126 . Controller  114  causes write element  122  to record magnetic patterns of data on a writable surface of disk  124  in tracks  128 . The controller  114  positions the read head  120  and write head  122  over the recordable or writable surface  124  of disk  126  by locking a servo loop to predetermined servo positioning burst patterns, typically located in servo spokes or zones. The predetermined servo positioning pattern may include a preamble field, a servo sync-mark (SSM) field, a track/sector identification (ID) field, a plurality of position error signal (PES) fields, and a plurality of repeatable run out (RRO) fields following the burst fields. In accordance with some embodiments of the invention, system  100  includes a cache memory  130 , for example, implemented with one or more of: a flash memory, a dynamic random access memory (DRAM), or a static random access memory (SRAM). 
         [0046]    System  100  including the host computer  102  and the storage device or HDD  104  is shown in simplified form sufficient for understanding the present invention. The illustrated host computer  102  together with the storage device or hard disk drive  104  is not intended to imply architectural or functional limitations. The present invention may be used with various hardware implementations and systems and various other internal hardware devices. 
       Basic Granular HAMR Data Storage Medium Design 
       [0047]      FIG. 2  is a schematic side view diagram  200  of a basic granular HAMR media design as is familiar to those skilled in the art. The storage medium fabrication process typically begins with a high temperature glass disk  202 , onto which a magnetic or non-magnetic adhesion layer  204  is deposited, typically comprising 10-200 nm of an amorphous adhesion layer material, CrTa, NiTa, or an amorphous soft underlayer (SUL)-like material such as CoFeZrB, CoTaZr, CoCrZr, CoFeTaZr, CoFeZrBW, or any combination of these materials. Next, a combined heat sink and plasmonic underlayer  206  is deposited, typically comprising 5 to 200 nm of Ag, Al, Cu, Cr, Au, NiAl, NiTa, Ru, RuAl, W, Mo, Ta or any combination of these materials. A third deposition creates a thin seed layer  208 , which can also act as a thermal barrier, typically comprising 2 to 50 nm MgO, TiN, SrTiO 3 , MgTi-oxide, and/or MgO x —SiO x  for which the 002 crystallographic orientation is chosen to determine the subsequent crystallographic orientation of a 002-oriented FePt layer whose growth is controlled by the seed layer. The use of seed layers to control the growth of magnetic data storage layers is familiar to those skilled in the art. Finally, a fourth layer of co-deposited L1 0  FePt, FePd, FePtAg, FePtAu, FePtCu, FePtNi, MnAl, and/or L1 1  CoPt, CoPd, etc.  210  and a segregant  212  is formed using a high temperature deposition. Segregants may typically comprise one or more of C, SiO x , TiO x , SiN x , BN x , B 2 O 3  and other nitrides, oxides, borides, and/or carbides. During this fourth deposition, the function of the segregant is to cause the HAMR material to separate out ideally into columnar (˜3-12 nm diameter) grains with uniform size distribution. These grains should be chemically distinct and isolated due to the segregant surrounding each grain to prevent contact between neighboring grains. The distribution of grain sizes in the HAMR layer may be characterized by two parameters: grain diameter and grain pitch, corresponding to the spacing between the centers of neighboring grains. Grain diameters have a mean value &lt;D&gt; with a standard deviation σ D , which is typically calculated while excluding grains smaller than ˜4 nm since these smaller grains cannot be used to store data due to their very low coercivity and thermal instability (see  FIG. 12 ). The grain pitch has a mean value &lt;P&gt; with a standard deviation σ P . One pathway for improvement is to reduce the two standard deviations to below 10 to 15% of the respective mean values, i.e. to make σ D &lt;[0.10 to 0.15&lt;D&gt;] and to make σ P &lt;[0.10 to 0.15&lt;P&gt;]. Finally, a carbon overcoat layer  214  is deposited to cover the layer with grains  210  and segregant  212 . The terms “grain size” and “grain diameter” are used interchangeably, and correspond to the distance from one grain edge to an opposing grain edge. The term “grain pitch” refers to the distance between the center of a grain and the center of a neighboring grain. The grain size distribution corresponds to the range of measured grain sizes or grain diameters in a deposited magnetic storage medium. The grain pitch distribution corresponds to the range of measured grain pitches in a deposited magnetic storage medium. Between neighboring grains, there will always be a segregant material typically with a thickness ranging from 0.5 to 2.0 nm which magnetically isolates neighboring grains. 
         [0048]      FIG. 3  is a schematic diagram of an Al to L1 0  chemical ordering transition. Initially, a film deposited at room temperature comprising co-deposited FePt, FePd, FePtAg, FePtAu, FePtCu, FePtNi, MnAl, CoPt, CoPd, etc. and a segregant will have no chemical ordering (phase Al with chemical ordering parameter S˜0), corresponding to view  300 , with lattice sites randomly containing, for example, either Fe  302  or Pt 304 atoms. After heating to 300 to 700° C., a chemical ordering transition  320  occurs, leading to the layered superlattice in view  350 , wherein layers of Fe atoms  352  alternate with layers of Pt atoms  354 . Such layered structures are characterized by substantially different magnetic properties perpendicular and parallel to the atomic layers  352  and  354 . The chemical ordering parameter for a superlattice in which layers have only one type of atom is defined as S=1.0, i.e. full 100% chemical ordering. 
         [0000]    Granular HAMR Media with Larger Grains 
         [0049]      FIG. 4  is a plan view TEM micrograph  400  of a granular HAMR medium with larger grains. A larger grain  402  and a smaller grain  404  may be seen, along with regions of segregant  406  which completely surround the grains thereby making them chemically distinct and isolated. A scale bar  408  corresponds to 50 nm.  FIG. 6  is a side view TEM micrograph  600  of the granular HAMR medium from  FIG. 4 . A grain  602  may be seen, along with a segregant region  604  and a 20 nm scale bar  606 . 
         [0050]      FIG. 8  is a histogram  800  of the grain size distribution for the HAMR medium shown in  FIGS. 4 and 6 . The number of counts  804  for various grain diameters  802  is shown—the maximum  806  of the distribution is 10.4 nm grain diameter, with a large standard deviation σ D  of 18%. The region  808  of grain diameters smaller than ˜4 nm is neglected since these small grains have low coercivities (see  FIG. 12 ) and thus cannot store data (since they will not remain magnetized in any direction reliably). 
         [0000]    Granular HAMR Media with Smaller Grains 
         [0051]      FIG. 5  is a plan view TEM micrograph  500  of a granular HAMR medium with smaller grains and a reduced number of grains with diameters smaller than ˜4 nm, corresponding to improvements from the process used to fabricate the HAMR medium with larger grains and a high number of grains smaller than ˜4 nm in  FIGS. 4, 6, and 8 . A larger grain  502  and a smaller grain  504  may be seen, along with regions of segregant  506  which completely surround the grains thereby making them chemically distinct and isolated. A scale bar  508  corresponds to 50 nm.  FIG. 7  is a side view TEM micrograph  700  of the granular HAMR medium from  FIG. 5 . A grain  702  may be seen, along with a segregant region  704  and a 20 nm scale bar  706 . 
         [0052]      FIG. 9  is a histogram  900  of the grain size distribution for the HAMR medium shown in  FIGS. 5 and 7 . The number of counts  904  for various grain diameters  902  is shown—the maximum  906  of the distribution is 8.4 nm grain diameter, with no change in standard deviation σ D  (18%) compared with  FIG. 8 . The region  908  of grain diameters smaller than ˜4 nm is neglected as for  FIG. 8 . Comparison of  FIGS. 8 and 9  shows that the most likely grain diameter (i.e., the mode of the distribution) has been reduced from 10.4 nm to 8.4 nm, and the frequency of grains with diameters less than ˜4 nm has been reduced. However, the standard deviation of the distribution did not change. 
         [0053]    As the grain sizes are made smaller, the variation, σ P , in grain pitch, P, is found to increase. Also, experiments and modeling have shown that both the chemical ordering (e.g., the extent to which the layers of Fe and Pt atoms—see view  350  in  FIG. 3 —contain only one atomic species) and the Curie temperatures of individual grains strongly depend on the grain size variation (see  FIGS. 11-13 ). Smaller grains down to 4 nm reduce the chemical ordering by 10-20% (see  FIG. 11 ), and this lower chemical ordering then reduces the Curie temperature (see  FIG. 12 ). Combining these two correlations gives  FIG. 13 , showing the reduction in normalized Curie temperatures as a function of the grain size. Thus with the smaller grain sizes needed to increase the storage medium areal density (measured in Tb/in 2 ), it is critical to reduce σ D  in order to minimize the variation in Curie temperatures, σ TC , in order to ensure the thermal stability and writability of HAMR storage systems. 
       Magnetic Hysteresis Curves for Anisotropic HAMR Media 
       [0054]      FIG. 10  shows a graph of the normalized magnetization  1004  as a function of the applied magnetic field  1002  (in kOersteds) for anisotropic HAMR materials (such as in view  350  in  FIG. 3 ). In-plane (where “plane” corresponds to the surface of the storage medium), the hysteresis curve has two components: section  1010  corresponding to the change in magnetization as the field is reduced, while section  1012  corresponds to the magnetization as the field is increased. Out-of-plane, the corresponding components of the hysteresis curve are 1008 and 1006, respectively. For magnetically isotropic materials (such as view  300  in  FIG. 3 ), the in-plane and out-of-plane hysteresis curves would be identical. For highly anisotropic superlattices, such as L1 0  FePt, the out-of-plane hysteresis curve shows a much higher coercivity (points  1014  and  1016 ) and magnetization at zero field than does the in-plane curve (points  1018  and  1020 ). This indicates that the magnetization direction of the grain when written to by the write head of a HAMR data storage system will tend to be roughly perpendicular to the plane of the storage medium (i.e., out-of-plane). 
       Relations Between the Chemical Order Parameter, Grain Diameter, and Curie Temperature 
       [0055]      FIGS. 11-13  relate to the three parameters: chemical order S, grain diameter, and Curie temperature. As is known in the art, the Curie temperature, T C , is the temperature where the magnetic moments in a material spontaneously order as the temperature goes below T C . The interrelations between these three parameters influence the performance of any HAMR medium.  FIGS. 11 and 12  are from C. B. Rong, et al., Adv. Mat., vol. 18, 2984 (2006).  FIG. 13  is from H. M. Lu, et al., J. Appl. Phys., vol. 103, 123526 (2008). 
         [0056]      FIG. 11  is a graph  1100  of the chemical order parameter S  1104  as a function of the grain diameter D  1102 . Curve  1110  shows a monotonic decrease with decreasing grain diameters, demonstrating that the degree of chemical ordering is negatively influenced by smaller grains—this may be due to the lower ratio of surface to volume in these larger grains, since surface effects (where the Fe and Pt atoms interact with segregant atoms) may tend to act against the chemical ordering process Al→L1 0 . Data point  1108  at 15 nm grain diameter shows nearly perfect chemical ordering of S=˜1.0, i.e., in  FIG. 3 , view  350 , layers  352  and  354  would each comprise essentially only a single atomic species, e.g. either Fe or Pt, but not both. Conversely, data point  1106  for 4 nm grain diameter shows much lower chemical ordering around 0.8, and below 4 nm the chemical ordering curve  1110  drops rapidly. 
         [0057]      FIG. 12  is graph  1200  of the Curie temperature T C    1204  as a function of the chemical order parameter S  1202 . Thus the horizontal axis  1202  here corresponds to the vertical axis  1104  in  FIG. 11 . Although there is substantial spread in the measured values  1206  for the Curie temperatures of individual grains, a linear fit  1208  shows a steady increase in Curie temperatures as a function of the chemical ordering parameter S—as is to be expected since the purpose of employing high uniaxial perpendicular anisotropy magnetic materials including superlattices like L1 0  or L1 1  is to take advantage of their substantial coercivities and remnant magnetization along the axes perpendicular to the superlattice planes. 
         [0058]      FIG. 13  is a graph  1300  of the normalized Curie temperature  1304  as a function of the grain diameter  1302 . The normalization uses the Curie temperatures, T C (∞), for infinitely large magnetic domains which are always higher than the Curie temperatures for finite-diameter grains. Here, horizontal axis  1302  corresponds to horizontal axis  1102  in  FIG. 11 , while the vertical axis  1304  has been normalized relative to the vertical axis  1204  in  FIG. 12 . Since the relationship in  FIG. 12  is linear with a small positive slope,  FIGS. 11 and 13  are similar, since they are connected through  FIG. 12 . Curve  1310  approaches a value of S=1.0 for the largest grain diameters  1308 —this corresponds to data point  1108  in  FIG. 11 . Data point  1306  shows a reduced normalized Curie temperature for grain diameters around 4 nm—corresponding to data point  1106  in  FIG. 11 . For grain diameters below 4 nm, the normalized Curie temperature may be seen to decrease rapidly. 
       FIGS.  14 - 16   
     First Embodiment 
       [0059]      FIG. 14  is schematic diagram of the initial steps  1400  and  1450  in a templated growth process for a HAMR storage medium with a patterned (002)-oriented seed layer, corresponding to a first embodiment of the present invention. A high temperature glass substrate  1402  forms a surface upon which an adhesion layer  1404  is grown, typically comprising 10 to 200 nm of an amorphous adhesion layer material, CrTa, NiTa, or an amorphous soft underlayer (SUL)-like material such as CoFeZrB, CoTaZr, CoCrZr, CoFeTaZr, CoFeZrBW, or any combination of these materials. Next a very thin seed or onset layer may optionally be deposited prior to depositing heat sink layer  1410 , typically comprising 5 to 200 nm of Ag, Al, Cu, Cr, Au, NiAl, NiTa, Ru, RuAl, W, Mo, Ta or any combination of these materials. The two layers  1404  and  1410  are collectively shown as a first underlayer stack  1452  in view  1450 . On top of layer  1410 , a 2 to 50 nm layer  1412  of (002) oriented MgO followed by a 3 to 20 nm layer  1414  of (002) oriented TiN are deposited—both these depositions are typically at room temperature. The combination of layers  1412  and  1414  forms a second underlayer stack, wherein the second underlayer stack may comprise only layer  1412 , only layer  1414 , or both layers  1412  and  1414  or other layers or combinations of materials including (002) magnesium oxide, (002) titanium nitride, both (002) magnesium oxide and (002) titanium nitride, and/or combinations of materials including (002) strontium titanium-oxide, (002) magnesium titanium-oxide, and/or (002) magnesium oxide-silicon oxide. These materials may be co-deposited and/or deposited in sequential multilayer depositions to form the overall second underlayer stack. The second underlayer stack constitutes the material for the patterned seed layer  1502  in  FIG. 15 , thus the orientation of the second underlayer stack material is important for controlling the orientation of the HAMR storage layer  1602  grown on the patterned seed layer  1502  in  FIG. 16 . The second underlayer stack may comprise either one or two layers: a first upper layer and an optional second lower layer. The first upper layer is patterned to form the patterned seed layer  1502  in  FIG. 15 . 
         [0060]    View  1450  in  FIG. 14  shows a deposition of a hard mask layer  1454  which may comprise high density carbon, corresponding to carbon with a higher degree of sp 3  bonding (and a correspondingly lower degree of sp 2  bonding) which has characteristically higher etch contrast and higher density than more graphitic carbon (i.e., carbon with more sp 2  bonding). In addition to high density carbon, other possible materials for the hard mask layer comprise one or more layers of carbon nitride, boron nitride, silicon nitride, and/or silicon oxide. Following the deposition of hard mask layer  1454 , a resist layer  1456  is deposited. Layer  1456  is then lithographically patterned (e.g., using imprint lithography) by an imprint template  1458 . The template is pressed (downward arrow) into the resist layer  1456 . After imprinting, template  1458  is pulled off the resist  1456  (upward arrow), leaving behind a pattern of raised features in the resist layer  1456 , surrounded by lower features. 
         [0061]      FIG. 15  is a schematic diagram of an intermediate step  1500  in a templated growth process for a HAMR storage medium with a patterned seed layer  1502  following the steps shown in  FIG. 14 . Here, an ion milling step has been used to transfer the pattern in resist layer  1456  down through the hard mask layer  1454  and through the seed layer  1414  to form patterned seed layer  1502 . The seed layer  1414  comprises the material deposited to form the first layer in the second underlayer stack. After this patterning process is complete, the remainder of the resist layer  1456  and the hard mask layer  1454  are removed, exposing a set of seed layer pillars  1502  with the proper crystallographic orientation for subsequent growth of the HAMR layer  1602  in  FIG. 16 . If a second layer is present in the second underlayer stack, it is not patterned, and remains as a continuous unpatterned layer  1412  underneath the patterned seed layer  1502  as illustrated in  FIG. 15 . 
         [0062]      FIG. 16  is a schematic diagram of the final step  1600  in a templated growth process for a HAMR storage medium with a patterned seed layer  1502 , typically comprising (002) TiN, MgO, SrTiO 3 , MgTi-oxide, and/or MgO x —SiO x  as characterized in  FIG. 14 . A key requirement for the seed layer  1502  is the ability to withstand high temperature depositions. The HAMR material  1602  is deposited using shadow growth on the raised pillars in the patterned seed layer  1502 . Growth is shadowed when the raised pillars  1502  have sufficiently high aspect ratios to prevent (by shadowing) any growth in the regions between pillars  1502 . The deposition of the HAMR storage medium  1602  is done at high temperatures, typically 300 to 700° C. and nucleation is preferentially on the tops of the pillars  1502 —this is a key difference between the method of the present invention and low temperature deposition processes for patterned PMR storage media. For the first embodiment, the sizes and shapes of the patterned pillars  1502  control the sizes and shape of the magnetic grains  1602 . 
       FIGS.  17 - 19   
     Second Embodiment 
       [0063]      FIG. 17  is schematic diagram of the initial steps  1700  and  1750  in a templated growth process for a HAMR storage medium with a patterned metal seed layer, corresponding to a second embodiment of the present invention. A high temperature glass substrate  1702  forms a surface upon which an adhesion layer  1704  is grown, typically comprising 10 to 200 nm of an amorphous adhesion layer material, CrTa, NiTa, or an amorphous soft underlayer (SUL)-like material such as CoFeZrB, CoTaZr, CoCrZr, CoFeTaZr, CoFeZrBW, or any combination of these materials. Next a very thin seed or onset layer may optionally be deposited prior to depositing heat sink layer  1710 , typically comprising 5 to 200 nm of Ag, Al, Cu, Cr, Au, NiAl, NiTa, Ru, RuAl, W, Mo, Ta or any combination of these materials. The two layers  1704  and  1710  are collectively shown as a first underlayer stack  1752  in view  1750 . 
         [0064]    On top of layer  1710 , a 2 to 50 nm layer  1712  of (002) oriented MgO followed by a 3 to 20 nm layer  1714  of (002) oriented TiN are deposited—both these depositions are typically at room temperature. The combination of layers  1712  and  1714  forms a second underlayer stack, wherein the second underlayer stack may comprise only layer  1712 , only layer  1714 , or both layers  1712  and  1714  or other layers or combinations of materials including (002) magnesium oxide, (002) titanium nitride, both (002) magnesium oxide and (002) titanium nitride, and/or combinations of materials including (002) strontium titanium-oxide, (002) magnesium titanium-oxide, and/or (002) magnesium oxide-silicon oxide. These materials may be co-deposited and/or deposited in sequential multilayer depositions to form the overall second underlayer stack. 
         [0065]    Next an additional 3 to 50 nm metallic layer  1716  is formed from one or more successive deposition steps. In some embodiments, a first step deposits one or more metal layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt, wherein each layer may comprise one or more of these metals, and where there is no underlayer of CrRu, RuAl, etc., In other embodiments, a first step deposits an underlayer of (002)-oriented CrRu, RuAl, CrA, and/or RuA alloys (where A is another metal) followed by a second step to deposit one or more metal layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt wherein each layer may comprise one or more of these metals. The metal layer deposition is performed at elevated temperatures, typically at least 300° C. The metal layers for generating a patterned layer is the key difference between the structures illustrated in  FIGS. 17-19  and the structures illustrated for the first embodiment in  FIGS. 14-16 . In order to achieve the necessary (002) orientation of these metal layers, deposition must be performed at high temperatures, typically at least 300° C. Advantages of using a metal such as Pt or Pd as the patterned seed layer, instead of the previously-used MgO and/or TiN, include 1) better wetting of the HAMR material, 2) an increase in etch rates of the metal layer relative to MgO or TiN seed layers to achieve higher aspect ratios, 3) increased etch depth enabling use of increased pillar heights (higher aspect ratios so that the magnetic layer will only nucleate on the upper surface), and 4) a reduction in pattern-transfer induced damage (better crystallinity) to the seed layer arising from shorter etch times (due to the higher metal etch rates) to produce better alignment of (002)-oriented grains (high K u  is out-of-plane), thereby giving improved magnetic properties in the storage layer. In the structure of  FIGS. 17-19 , layer  1716  is patterned, instead of layer  1714  (corresponding to layer  1414  in  FIG. 14 ). The combinations of materials described here for the second embodiment should produce a smooth surface (RMS&lt;1 nm), have a high etch rate, and promote wettability of high uniaxial perpendicular anisotropy magnetic materials. 
         [0066]    View  1750  in  FIG. 17  shows a deposition of a hard mask layer  1754 , which may comprise high density carbon, carbon nitride, boron nitride, silicon nitride, and/or silicon oxide, etc. as in  FIG. 14 . Following the deposition of hard mask layer  1754 , a resist layer  1756  is deposited. Layer  1756  is then lithographically patterned (e.g., using imprint lithography) by a template  1758  as in  FIG. 14 . 
         [0067]      FIG. 18  is a schematic diagram of an intermediate step  1800  in a templated growth process for a HAMR storage medium with a patterned metal seed layer  1802 . Here, an etch step has been used to transfer the pattern in resist layer  1756  down through the hard mask layer  1754  and through the metal seed layer  1716  to form patterned metal seed layer  1802 . After this patterning process is complete, the remainder of the resist layer  1756  and the hard mask layer  1754  are removed, exposing seed layer pillars  1802  comprising the original composition of layer  1716  and with the proper orientation for subsequent growth of the HAMR layer  1902  in  FIG. 19 . 
         [0068]      FIG. 19  is a schematic diagram of the final step  1900  in a templated growth process for a HAMR storage medium with a patterned metal seed layer  1802 . The HAMR material  1902  is deposited using shadowed growth on the raised pillars in the patterned metal seed layer  1802 . Growth is shadowed when the raised pillars  1802  have sufficiently high aspect ratios to prevent (by shadowing) any growth in the regions between pillars  1802  (which would be onto the surface of layer  1714 ). The deposition of the HAMR storage medium  1902  is done at high temperatures, typically 300 to 700° C. and nucleation is preferentially on the tops of the pillars  1802 —this elevated temperature is a key difference between the method of the present invention and low temperature deposition processes for patterned PMR storage media. For the second embodiment, the sizes and shapes of the patterned pillars  1802  control the sizes and shape of the magnetic grains  1902 . 
       FIGS.  20 - 23   
     Third Embodiment 
       [0069]      FIG. 20  is a schematic diagram of the initial steps  2000  and  2050  in a hole-tone templated growth process for a HAMR storage medium, corresponding to a third embodiment of the invention. In a hole-toned growth process, the HAMR storage medium grains are formed in the holes of the template, in contrast with the first and second embodiments where the data storage medium grains are formed on the seed layer pillars. A high temperature glass substrate  2002  forms the surface upon which an adhesion layer  2004  is grown, typically comprising 10 to 200 nm of an amorphous adhesion layer material, CrTa, NiTa, or an amorphous soft underlayer (SUL)-like material such as CoFeZrB, CoTaZr, CoCrZr, CoFeTaZr, CoFeZrBW, or any combination of these materials. Next a very thin seed or onset layer may optionally be deposited prior to depositing heat sink layer  2010 , typically comprising 5 to 200 nm of Ag, Al, Cu, Cr, Au, NiAl, NiTa, Ru, RuAl, W, Mo, Ta or any combination of these materials. The two layers  2004  and  2010  are collectively shown as a first underlayer stack  2052  in view  2050 . In this embodiment, the templating layer is between the heat sink layer and the HAMR storage medium layer. 
         [0070]    On top of layer  2010 , a 2 to 50 nm layer of (002) oriented MgO  2012  followed by a 3 to 20 nm layer of (002) oriented TiN  2014  are deposited—both these depositions are typically at room temperature. The combination of layers  2012  and  2014  forms a second underlayer stack, wherein the second underlayer stack may comprise only layer  2012 , only layer  2014 , both layers  2012  and  2014 , or other layers or combinations of materials including (002) magnesium oxide, (002) titanium nitride, both (002) magnesium oxide and (002) titanium nitride, and/or combinations of materials including (002) strontium titanium-oxide, (002) magnesium titanium-oxide, and/or (002) magnesium oxide-silicon oxide. These materials may be co-deposited and/or deposited in sequential multilayer depositions to form the overall second underlayer stack. The structure could also comprise an additional 3 to 50 nm metallic layer (not shown) deposited onto layer  2014  using one or more successive deposition steps. In some embodiments, a first step deposits one or more metal layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt, wherein each layer may comprise one or more of these metals, and where there is no underlayer of CrRu, RuAl, etc. In other embodiments, a first step deposits an underlayer of (002)-oriented CrRu, RuAl, CrA, and/or RuA alloys (where A is another metal) followed by a second step to deposit one or more metal layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt wherein each layer may comprise one or more of these metals. The metal layer deposition is performed at elevated temperatures, typically at least 300° C. The combinations of materials described here for the third embodiment should produce a smooth surface (RMS&lt;1 nm), and promote wettability of high uniaxial perpendicular anisotropy magnetic materials. 
         [0071]    View  2050  in  FIG. 20  shows a deposition of a template material (TM) layer  2054 . Template material layer may comprise high density carbon, carbon nitride, boron nitride, silicon nitride, and/or silicon oxide or other hard mask material layers that are also segregants, such as high density carbon, carbon nitride, boron nitride, silicon nitride, silicon oxide, titanium oxide, boron oxide, and other nitrides, oxides, borides and/or carbides for FePt (or other high K u  magnetic materials). Next, a resist layer  2056  is deposited. Layer  2056  is then lithographically patterned using a template  2058 , also as in  FIGS. 14 and 17 . 
         [0072]      FIG. 21  is a schematic diagram of an intermediate step  2100  in a hole-tone templated growth process for a HAMR storage medium. Here, the pattern in resist layer  2056  has been transferred into the TM layer  2054 , typically using a reactive ion etch (RIE) process, to form hole-tone patterned template layer  2102 . The hole-tone template  2102  corresponds to a structure with an ordered array of holes over a textured seed layer  2014 , rather than the pillars in the first and second embodiments. The use of a hole-tone template distinguishes the third embodiment from the first and second embodiments. After this patterning process is complete, the remainder of the resist layer  2056  is removed, exposing walls  2102  which may comprise high density carbon, carbon nitride, boron nitride, silicon nitride, silicon oxide, boron oxide, titanium oxide, and other nitrides, oxides, borides and/or carbides—these walls  2102  surround holes into which the magnetic storage medium grains  2204  will be formed in  FIG. 22 , rather than on top of the pillars as in the first and second embodiments. The materials in the walls  2102  must be capable of withstanding the high temperatures required for deposition of HAMR storage media. In this embodiment of the present invention, the contrast is reversed relative to the patterning technique in  FIGS. 14-19 . 
         [0073]    High temperature surface diffusion of the deposited HAMR storage medium  2204 , deposited typically at 300 to 700° C., facilitates growth of grains  2204  of magnetic material within the holes of the template  2102 , wherein the crystallographic orientation is controlled by the underlying seed layer  2014  or by an optional additional metal seed layer which is deposited on top of layer  2014  (which then does not function as the seed layer), typically comprised of (002) TiN, MgO, SrTiO 3 , MgTi-oxide, and/or MgO x —SiO x . The structure could also comprise an additional 3 to 50 nm metallic layer (not shown) deposited onto layer  2014 , of one or more layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt or a combination of (002)-oriented CrRu, RuAl, CrA, and/or RuA alloys (where A is another metal) followed by one or more layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt in which the deposition must be performed at high temperatures, typically at least 300° C. The shapes and sizes of the grains are controlled by shapes and sizes of the holes in the template  2102 . Dewetting of HAMR material from the template may facilitate diffusion of the HAMR material into the holes, increasing the heights of the individual magnetic storage locations. The template  2102  may comprise high density carbon, carbon nitride, boron nitride, silicon nitride, silicon oxide, boron oxide, titanium oxide, and other nitrides, oxides, borides and/or carbides. 
         [0074]      FIG. 22  is a schematic diagram of one possible final step  2200  in a hole-tone templated growth process for a HAMR storage medium. The HAMR material is deposited at temperatures between 300 and 700° C. into the holes formed in the template layer  2102 —thus the dimensions of the FePt grains are defined by the holes (thus the term “hole-tone template”) and the crystallographic orientation of the FePt grains will be determined by the underlying seed layer  2014  which is unpatterned and thus has not been affected by potential pattern-transfer process defect generation. In this embodiment of the invention, the two functions of defining magnetic grain dimensions and shape, and crystallographic orientation control are separated: layer  2102  determines the magnetic grain dimensions/shape, while layer  2014  controls the crystal orientation of the HAMR storage medium grains. 
         [0075]    Suitable materials for the hole tone template matrix layer comprise hard mask materials: high density carbon, carbon nitride, boron nitride, silicon nitride, and/or silicon oxide, and natural segregants for FePt or other high K u  magnetic materials such as C, SiO x , TiO x , SiN x , BN x , B 2 O 3  and other nitrides, oxides, borides, and/or carbides. Advantages of the hole tone template structure include: 1) the sole use of an RIE pattern transfer process from the resist  2056  into the template material  2054 , thereby reducing damage to the seed layer that may occur due to ion beam milling in the pattern transfer process—this reduced damage may improve the quality of the epitaxial growth process and the crystalline orientation of the HAMR storage medium grains, 2) removal of the template (see  FIG. 23 ) after HAMR material deposition allows complete segregation of HAMR medium islands without the need for segregants, however segregants can also be used. 
         [0076]      FIG. 23  is a schematic diagram of an alternative final step  2300  in a hole-tone templated growth process for a HAMR storage medium, comprising an additional step following  FIG. 22  in which the hole tone template layer  2102  has been removed, leaving magnetic grains  2204  separated by gaps, instead of the walls  2102  in the template material. 
       FIGS.  24 - 25   
     Fourth Embodiment 
       [0077]      FIG. 24  is a schematic diagram  2400  of steps in a hybrid templated growth process for a HAMR storage medium, corresponding to a fourth embodiment of the invention which is similar to the first and second embodiments except that the seed layer islands have a lower aspect ratio which does not cause shadowing of the HAMR layer deposition. The preceding process steps before the steps shown in  FIG. 24  are similar to those shown for the first and second embodiments in  FIGS. 14-19  except as explained below. View  2400  in  FIG. 24  corresponds to  FIG. 16  with these correspondences: glass substrate  2402  ( FIG. 16 :  1402 ), first underlayer stack  2452  ( FIG. 16 :  1452 ), and MgO layer  2412  ( FIG. 16 :  1412 ). The HAMR storage material is deposited  2404  at high temperatures, typically 300 to 700° C. on the raised islands  2408  of the patterned seed layer as well as into the holes formed by the raised islands  2408  onto the underlying seed layer  2412 . Note that here the aspect ratio of features  2408  is lower than for features  1502  in  FIGS. 15 and 18 , thus magnetic material  2406  is deposited between features  2408  and also deposited  2404  on top of features  2408 —this occurs because the shadowing effect which prevented deposition of magnetic material between features  1502  in  FIGS. 15 and 18  is much less pronounced here. The HAMR material  2404  is polycrystalline since template  2408  is not as good a seed layer as layer  2412  due to surface damage occurring during processing, while HAMR material  2406  has less processing damage hence better crystallinity with an (002) orientation controlled by (002) seed layer  2412 . In some embodiments, layer  2408  may comprise (002) TiN and seed layer  2412  may comprise (002) MgO. In other embodiments, layer  2408  may comprise a metal and layer  2412  may comprise (002) TiN. The structure may also comprise an additional 3 to 50 nm metallic layer formed from one or more successive deposition steps. In some embodiments, a first step deposits one or more metal layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt, wherein each layer may comprise one or more of these metals, and where there is no underlayer of CrRu, RuAl, etc. In other embodiments, a first step deposits an underlayer of (002)-oriented CrRu, RuAl, CrA, and/or RuA alloys (where A is another metal) followed by a second step to deposit one or more metal layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt wherein each layer may comprise one or more of these metals. The metal layer deposition is performed at elevated temperatures, typically at least 300° C. 
         [0078]    View  2450  in  FIG. 24  illustrates the hybrid component of the growth process illustrated in view  2400 . Following view  2400 , the polycrystalline HAMR material  2404 , which would not be a good magnetic data storage material since its poor crystallinity leads to misaligned grains (high K u  axis is not aligned out-of-plane), may be removed by a lift off process in which the patterned layer  2408  is removed, thereby removing depositions  2404 . 
         [0079]      FIG. 25  shows an alternative final step for the fourth embodiment in which the polycrystalline FePt  2404  has been removed by a planarization process that polishes off the raised polycrystalline FePt layer  2404  while leaving the recessed crystalline FePt  2406  and the patterned template layer  2408  unpolished. A third selective removal method may be a chemically-selective etch process. For any of the cases in views  2450  and  2500 , the recessed crystalline HAMR material regions  2406  remain as chemically-isolated, magnetic data storage islands. 
       FIGS.  26 - 29   
     Fifth Embodiment 
       [0080]      FIG. 26  is schematic diagram of the initial steps  2600  and  2650  in a templated growth process for a HAMR storage medium with a patterned (002)-oriented seed layer, corresponding to a fifth embodiment of the present invention. This embodiment is similar to the first, second, third, and fourth embodiments in  FIGS. 14-25 , except that an array of nanoparticles is used for the patterning of the hard mask, instead of a resist layer patterned with lithographic methods. 
         [0081]    A high temperature glass substrate  2602  forms a surface upon which an adhesion layer  2604  is grown, typically comprising 10-200 nm of an amorphous adhesion layer material, CrTa, NiTa, or an amorphous soft underlayer (SUL)-like material such as CoFeZrB, CoTaZr, CoCrZr, CoFeTaZr, CoFeZrBW, or any combination of these materials. Next a very thin seed or onset layer may optionally be deposited prior to depositing a 5 to 200 nm heat sink layer  2610 , typically comprising 5 to 200 nm of Ag, Al, Cu, Cr, Au, NiAl, NiTa, Ru, RuAl, W, Mo, Ta or any combination of these materials. The two layers  2604  and  2610  are collectively shown as a first underlayer stack  2652  in view  2650 . On top of layer  2610 , a 2 to 50 nm layer  2612  of (002) oriented MgO followed by a 3 to 20 nm layer  2614  of (002) oriented TiN are deposited—both these depositions are typically at room temperature. The combination of layers  2612  and  2614  forms a second underlayer stack, wherein the second underlayer stack may comprise only layer  2612 , only layer  2614 , or both layers  2612  and  2614  or other layers or combinations of materials including (002) magnesium oxide, (002) titanium nitride, both (002) magnesium oxide and (002) titanium nitride, and/or combinations of materials including (002) strontium titanium-oxide, (002) magnesium titanium-oxide, and/or (002) magnesium oxide-silicon oxide. The structure may also comprise an additional 3 to 50 nm metallic layer formed from one or more successive deposition steps. In some embodiments, a first step deposits one or more metal layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt, wherein each layer may comprise one or more of these metals, and where there is no underlayer of CrRu, RuAl, etc. In other embodiments, a first step deposits an underlayer of (002)-oriented CrRu, RuAl, CrA, and/or RuA alloys (where A is another metal) followed by a second step to deposit one or more metal layers of (002)-oriented Pt, Pd, Ir, Rh, Os, or FePt wherein each layer may comprise one or more of these metals. The metal layer deposition is performed at elevated temperatures, typically at least 300° C. 
         [0082]    View  2650  in  FIG. 26  shows a deposition of a hard mask layer  2654  which may comprise high density carbon, corresponding to carbon with a higher degree of sp 3  bonding (and a correspondingly lower degree of sp 2  bonding) which has characteristically higher etch contrast and higher density than more graphitic carbon (i.e., carbon with more sp 2  bonding). In addition to high density carbon, other possible materials for the hard mask layer comprise single layers or combinations of carbon nitride, boron nitride, silicon nitride, and/or silicon oxide. Following the deposition of hard mask layer  2654 , a layer of nanoparticles  2656  is deposited. Layer  2656  performs the same patterning function as resist layer  1456  in  FIG. 14 , with the advantages that smaller grain diameters and grain pitches are possible, and no lithographic patterning step is required—the nanoparticles in layer  2656  are self-organizing into a monodisperse nanoparticle array. 
         [0083]      FIG. 27  illustrates schematically a pattern transfer process in which the nanoparticles in layer  2656  form a mask to pattern the (unpatterned) hard mask layer  2654 , typically using an RIE process which is highly anisotropic, and thus transfers the shapes of the nanoparticles with high spatial resolutions into layer  2654  as shown, thereby creating patterned hard mask layer  2754  from the remaining material out of the original (unpatterned) hard mask layer  2654 . 
         [0084]      FIG. 28  illustrates the next step in the fifth embodiment of the invention in which the layer  2656  of nanoparticles has been removed and another pattern transfer process has transferred the pattern in patterned hard mask layer  2754  into (unpatterned) seed layer  2614  to form patterned seed layer  2814 . In an alternative embodiment, if a thin metal layer has been deposited on top of the second underlayer stack as described above, then this thin metal layer will function as the patterned seed layer instead of layer  2614 . 
         [0085]      FIG. 29  shows schematically the final steps in a templated growth process for a HAMR storage medium with the patterned seed layer  2814 , following the steps shown in  FIGS. 26-28 . The patterned hard mask layer  2754  has been removed, exposing a set of seed layer islands  2814 , typically comprising (002) TiN, MgO, SrTiO 3 , MgTi-oxide, MgO x —SiO x , Pt, Pd, Ir, Rh, Os, or FePt. The HAMR magnetic material is deposited  2902  using shadow growth on the islands  2814  in the seed layer. Growth is shadowed when the raised islands  2814  have sufficiently high aspect ratios to prevent (by shadowing) any growth in the regions between islands  2814  onto layer  2612 . The deposition of the HAMR storage medium  2902  is done at high temperatures, typically 300 to 700° C. and nucleation is preferentially on the tops of the islands  2814 —this is a key difference between the method of the present invention and low temperature deposition processes for patterned PMR storage media. 
       Alternative HAMR Storage Medium Materials 
       [0086]    In the above description of embodiments of the invention, the magnetic material has been characterized as an Iron-Platinum (FePt) alloy, with L1 0  superlattice ordering formed in a high temperature Al to L1 0  chemical ordering transition. Other magnetic alloys and chemical ordering transitions fall within the scope of the invention, including Iron-Palladium (FePd), Iron-Platinum-Silver (FePtAg), Iron-Platinum-Gold (FePtAu), Iron-Platinum-Copper (FePtCu), Iron-Platinum-Nickel (FePtNi), Manganese Aluminum (MnAl), wherein these alloys also undergo an Al to L1 0  chemical ordering transition. Also within the scope of the invention are Cobalt-Platinum (CoPt) and Cobalt-Palladium (CoPd) alloys undergoing a high temperature Al to L1 1  chemical ordering transition. Other magnetic compounds undergoing these, or similar, chemical ordering transitions may also fall within the scope of the invention. As is known in the art, heteroexpitaxial strain induced in these chemical ordered magnetic materials results in the high anisotropy direction being oriented perpendicular to the plane (see  FIG. 10 ). Typical segregants may include C, SiO x , TiO x , SiN x , BN x , B 2 O 3  and other nitrides, oxides, borides, and/or carbides. 
       Patterned Layers Relative to the Heat Sink Layer 
       [0087]    For proper dissipation of heat (due to the HAMR process) from the data storage layer, it is typically necessary that the heat sink layer be a continuous film, i.e., that the heat sink layer not be patterned, since patterning of the heat sink layer would prevent the optimal three-dimensional dissipation of heat. In embodiments of the invention, the templating procedure may be applied to one or more layers, as long as all of these layers are above the heat sink layer. In some embodiments, the one or more patterned layers may extend down to just above the top surface of the heat sink layer. In some embodiments, the one or more patterned layers may extend up to the lower surface of the media layer. 
       Alternative Embodiments 
       [0088]    Although embodiments have been described in the context of hard disk drives, it should be understood that various changes, substitutions and alterations can be made. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, or composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of embodiments, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.