Systems and methods for controlling damping of magnetic media for heat assisted magnetic recording

Information

  • Patent Grant
  • 9034492
  • Patent Number
    9,034,492
  • Date Filed
    Friday, January 11, 2013
    11 years ago
  • Date Issued
    Tuesday, May 19, 2015
    9 years ago
Abstract
Systems and methods for controlling the damping of magnetic media for heat assisted magnetic recording are provided. One such system includes a heat sink layer, a growth layer on the heat sink layer, a magnetic recording layer on the growth layer, where the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer, and a capping magnetic recording layer on the magnetic recording layer, the capping recording layer including a first material configured to increase a damping constant of the capping recording layer to a first preselected level.
Description
FIELD

The present invention relates to magnetic media used in storage systems, and more specifically to systems and methods for controlling the damping of magnetic media for heat assisted magnetic recording.


BACKGROUND

Perpendicular magnetic recording (PMR) is approaching the maximum areal density (AD) that can be achieved with multi-layer media in which the magnetic anisotropy field (Hk) is graded from a low value in the top layer to a high value in the lowest layer. Therefore alternate recording technologies such as heat assisted magnetic recording (HAMR), which may encompass or be synonymous with additional technologies such as energy assisted magnetic recording (EAMR), are being investigated to achieve higher areal density.


HAMR technologies are intended to address the areal density problem. In these assisted recording systems, a laser beam is delivered through an optical waveguide and interacts with a near field transducer (NFT) that absorbs part of the optical energy and forms a very strong localized electromagnetic field in the near field region. When the localized electromagnetic field is close enough to the recording medium, the recording medium absorbs part of the localized electromagnetic field energy and is thereby heated up thermally, which helps to realize the magnetic recording process.


Recent atomistic calculations associated with HAMR media switching have revealed a relatively severe fast cooling rate problem for HAMR media. More specifically, for the fast cooling rates needed to support HAMR in high speed applications, theoretical results have revealed that conventional HAMR media experience fluctuations in magnetization and anisotropy during fast cooling which will cause grains to flip when they should not and to not flip when they should. This will lead to wide and noisy transitions with poor bit error rate performance. In addition, this will lead to DC-like noise proximate to the transitions but not at them, which is due to the associated magnetization and anisotropy fluctuations. As such, an improved magnetic media for use in HAMR applications that addresses these problems is desirable.


SUMMARY

Aspects of the invention relate to systems and methods for controlling the damping of magnetic media for heat assisted magnetic recording. In one embodiment, the invention relates to a magnetic media structure for heat assisted magnetic recording, the media structure including a heat sink layer, a growth layer on the heat sink layer, a magnetic recording layer on the growth layer, where the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer, and a capping magnetic recording layer on the magnetic recording layer, the capping recording layer including a first material configured to increase a damping constant of the capping recording layer to a first preselected level.


In another embodiment, the invention relates to a magnetic media structure for heat assisted magnetic recording, the media structure including a heat sink layer, a growth layer on the heat sink layer, a magnetic recording underlayer on the growth layer, the underlayer including a first material configured to increase a damping constant of the underlayer to a first preselected level, and a magnetic recording layer on the underlayer, where the growth layer and the underlayer are configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer.


In yet another embodiment, the invention relates to a method for increasing a damping constant of a magnetic media structure for heat assisted magnetic recording, the method including providing a heat sink layer, providing a growth layer on the heat sink layer, providing a magnetic recording layer on the growth layer, where the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer, and providing a capping magnetic recording layer on the magnetic recording layer, the capping recording layer including a first material configured to increase a damping constant of the capping recording layer to a first preselected level.


In still yet another embodiment, the invention relates to a method for increasing a damping constant of a magnetic media structure for heat assisted magnetic recording, the method including providing a heat sink layer, providing a growth layer on the heat sink layer, providing a magnetic recording underlayer on the growth layer, the underlayer including a first material configured to increase a damping constant of the underlayer to a first preselected level, and providing a magnetic recording layer on the underlayer, where the growth layer and the underlayer are configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 is a side view of a heat assisted magnetic recording (HAMR) system including a read/write head positioned above a damped magnetic media in accordance with one embodiment of the invention.



FIG. 2
a is a side view of a damped magnetic media with a continuous doped capping layer positioned on a magnetic recording layer that can be used in conjunction with the read/write head of FIG. 1 in accordance with one embodiment of the invention.



FIG. 2
b is a side view of a damped magnetic media with a non-continuous doped capping layer positioned on a magnetic recording layer that can be used in conjunction with the read/write head of FIG. 1 in accordance with one embodiment of the invention.



FIG. 3
a is a side view of a damped magnetic media with a continuous doped underlayer positioned beneath a magnetic recording layer that can be used in conjunction with the read/write head of FIG. 1 in accordance with one embodiment of the invention.



FIG. 3
b is a side view of a damped magnetic media with a non-continuous doped underlayer positioned beneath a magnetic recording layer that can be used in conjunction with the read/write head of FIG. 1 in accordance with one embodiment of the invention.



FIG. 4 is a flowchart of a process for forming a damped magnetic media with a doped capping layer positioned on a magnetic recording layer in accordance with one embodiment of the invention.



FIG. 5 is a flowchart of a process for forming a damped magnetic media with a doped underlayer positioned beneath a magnetic recording layer in accordance with one embodiment of the invention.





DETAILED DESCRIPTION

Referring now to the drawings, embodiments of systems and methods for controlling the damping of magnetic media for heat assisted magnetic recording (HAMR) are illustrated. The systems can include a damped magnetic media with a continuous or non-continuous doped capping layer positioned on the recording layer, or a damped magnetic media with a continuous or non-continuous doped underlayer positioned beneath the recording layer, that can be used in conjunction with a HAMR read/write head. The methods can be used to form the various embodiments of the damped magnetic media. The doped capping layer or doped underlayer includes a first material (e.g., rare earth dopant) that is configured to increase a damping constant of the capping layer to a first preselected level. In many embodiments, a heat sink layer and growth layer are positioned beneath the recording layer and the doped capping layer or doped underlayer.


While not bound by any particular theory, the doped capping layer or doped underlayer can sharpen transitions and allow for faster cooling for higher data rates, higher thermal gradients, and higher linear density. It may also suppress certain types of noise. In effect, the doped capping layer or doped underlayer can be exchange coupled to the recording grains, and can thus absorb magnons (e.g., quantized magnetic fluctuations) that are generated at high temperatures and persist to low temperatures because the intrinsic damping of conventional HAMR media is low.



FIG. 1 is a side view of a heat assisted magnetic recording (HAMR) system 100 including a read/write head 102 positioned above a damped magnetic media 104 in accordance with one embodiment of the invention. The head 102 includes a write pole 106 consisting of a leading write pole 106a and a trailing write pole 106b, where a portion of the write pole 106 is enclosed by a pancake style write coil 108. The head 102 further includes a waveguide 110 consisting of a waveguide core 110a surrounded by a waveguide cladding 110b. The head 102 also includes a near field transducer (NFT) 112 positioned within the waveguide cladding 110b, and a NFT heat sink 114 to dissipate heat from the NFT 112. The operation of HAMR read/write heads and their components is well known in the art, and head 102 can be operated accordingly.


The damped magnetic media 104 includes a doped capping layer or doped underlayer made of a first material (e.g., rare earth dopant) that is configured to increase a damping constant of the capping layer to a first preselected level. In several embodiments, the first material is a rare earth dopant such as Ho. In one such case, the concentration of Ho is greater than about 0.5 percent. In other embodiments, the first material is a rare earth dopant that includes one or more materials from the group consisting of Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, or other suitable dopants.



FIG. 2
a is a side view of a damped magnetic media 204 with a continuous doped capping layer 214 positioned on a magnetic recording layer 212 that can be used in conjunction with the read/write head of FIG. 1 in accordance with one embodiment of the invention. The damped magnetic media 204 has a stacked multi-layer structure with a bottom heat sink layer 206, a thermal resistor layer 208 on the heat sink layer 206, a growth layer 210 on the thermal resistor layer 208, the recording layer 212 on the growth layer 210, and the continuous doped capping layer 214 on the recording layer 212. In some embodiments, an additional layer, such as an exchange coupling layer, is positioned between the doped capping layer 214 (e.g., capping magnetic recording layer) and the magnetic recording layer 212. In some embodiments, the heat sink 206 is on another additional layer (e.g., a substrate or a soft magnetic underlayer on a substrate).


The recording layer 212 consists of a number of discrete grains oriented in a vertical direction and can be made of FePt, CoCrPt, CoPt, CoPtNi, and/or other suitable materials. In several embodiments, the recording layer 212 consists of one or more materials suitable to provide an L10 crystalline structure. The doped capping layer 214 is made of a first material (e.g., a magnetic alloy with a rare earth dopant) that is configured to increase a damping constant of the capping layer 214 to a first preselected level. In one embodiment, the first preselected level is about 20% and corresponds to an overall damping of the media 204 of about 5%. In several embodiments, the first material is a rare earth dopant such as Ho or Ho oxide. In one such case, the concentration of Ho in the capping layer 214 is greater than about 0.5 percent. In other embodiments, the first material is a rare earth dopant that includes one or more materials from the group consisting of Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, or other suitable dopants.


In several embodiments, the first material or doping material is deposited on the grains of the recording layer 212 such that portions of the doping material are disposed between the grains. In one such embodiment, the volume average of damping is segmented such that about one third is contributed by the doped capping layer 214 and about two thirds is contributed by the recording layer 212 (e.g., by the doping material positioned between the grains). In several embodiments, the rare earth dopant for the doped capping layer 214 is selected for its ability to increase intrinsic damping and its capability to avoid disturbing a desired crystalline structure of the recording layer 212 (e.g., L10 crystalline structure).


The heat sink layer 206 is configured to dissipate heat and is made of one or more high thermal conductivity materials (e.g., an alloy of Cu and/or other thermally conductive materials). The optional thermal resistor layer 208 is configured to resist thermal conduction and is made of one or more materials suited for such (e.g., SiOx, WSe, and/or other suitable materials).


The growth layer 210 is configured to facilitate a growth of a preselected structure (e.g., L10 crystalline structure or other suitable structure) of the recording layer 212. In several embodiments, the growth layer 210 is made of one or more materials conducive to growing the preselected structure of the recording layer 212, such as MgO and/or other suitable materials. The optional exchange coupling layer positioned between the recording layer 212 and the doped capping layer 214 can be made of Ru and/or other suitable materials as are known in the art.


In several embodiments, the doped capping layer 214 and/or recording layer 212 increase the damping of the magnetic media 204 and therefore sharpen transitions and allow for faster media cooling for higher data rates, higher thermal gradients, and higher linear density while suppressing certain types of undesirable noise.



FIG. 2
b is a side view of a damped magnetic media 304 with a non-continuous doped capping layer 314 positioned on a recording layer 312 that can be used in conjunction with the read/write head of FIG. 1 in accordance with one embodiment of the invention. The damped magnetic media 304 has a stacked multi-layer structure with a bottom heat sink layer 306, a thermal resistor layer 308 on the heat sink layer 306, a growth layer 310 on the thermal resistor layer 308, the recording layer 312 on the growth layer 310, and the non-continuous (e.g., discrete) doped capping layer 314 on the recording layer 312. In some embodiments, an additional layer, such as an exchange coupling layer, is positioned between the doped capping layer 314 (e.g., capping magnetic recording layer) and the magnetic recording layer 312.


The recording layer 312 includes a number of discrete grains oriented in a vertical direction and can be made of FePt, CoCrPt, CoPt, CoPtNi, and/or other suitable materials. In several embodiments, the doped capping layer 314 includes a number of discrete grains in vertical correspondence with the grains of the recording layer 312. Similarly, the optional exchange coupling layer can include a number of discrete grains in vertical correspondence with the grains of the recording layer 312. The layers of the damped magnetic media 304 can otherwise function, and be made of the same materials, as described above for the damped magnetic media 204 of FIG. 2a.



FIG. 3
a is a side view of a damped magnetic media 404 with a continuous doped underlayer 414 positioned beneath a magnetic recording layer 412 that can be used in conjunction with the read/write head of FIG. 1 in accordance with one embodiment of the invention. The damped magnetic media 404 has a stacked multi-layer structure with a bottom heat sink layer 406, a thermal resistor layer 408 on the heat sink layer 406, a growth layer 410 on the thermal resistor layer 408, the continuous doped underlayer 414 on the growth layer 410, and the recording layer 412 on the continuous doped underlayer 414. In some embodiments, the stacked structure further includes a capping layer on the recording layer 412.


The recording layer 412 includes a number of discrete grains oriented in a vertical direction and can be made of FePt, CoCrPt, CoPt, CoPtNi, and/or other suitable materials. In several embodiments, the recording layer 412 is made of one or more materials providing for an L10 crystalline structure. The doped underlayer 414 is made of a first material (e.g., rare earth dopant) that is configured to increase a damping constant of the capping layer 414 to a first preselected level and to facilitate a growth of the recording layer 412 with a preselected crystalline structure. In one embodiment, the first preselected level is about 20% and corresponds to an overall damping of the media 404 of about 5%. In several embodiments, the first material is a rare earth dopant such as Ho or Ho oxide. In one such case, the concentration of Ho is about 0.5 percent or greater. In other embodiments, the first material is a rare earth dopant that includes one or more materials from the group consisting of Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, or other suitable dopants.


In several embodiments, the first material or doping material is deposited such that portions of the doping material are disposed between the grains of the recording layer 412. In one such embodiment, the volume average of damping is segmented such that about one third is contributed by the doped underlayer 414 and about two thirds is contributed by the recording layer 412 (e.g., by the doping material between the grains). In several embodiments, the rare earth dopant for the doped underlayer 414 is selected for its ability to increase intrinsic damping and its capability to avoid disturbing a desired crystalline structure of the recording layer 412.


The other layers of the damped magnetic media 404 can function, and be made of the same materials, as described above for the damped magnetic media 204 of FIG. 2a.



FIG. 3
b is a side view of a damped magnetic media 504 with a non-continuous doped underlayer 514 positioned beneath a magnetic recording layer 512 that can be used in conjunction with the read/write head of FIG. 1 in accordance with one embodiment of the invention. The damped magnetic media 504 has a stacked multi-layer structure with a bottom heat sink layer 506, a thermal resistor layer 508 on the heat sink layer 506, a growth layer 510 on the thermal resistor layer 508, the non-continuous (e.g., discrete) doped underlayer 514 on the growth layer 510, and the recording layer 512 on the continuous doped underlayer 514. In some embodiments, the stacked structure further includes a capping layer on the recording layer 512.


The recording layer 512 includes a number of discrete grains oriented in a vertical direction and can be made of FePt, CoCrPt, CoPt, CoPtNi, and/or other suitable materials. In several embodiments, the doped underlayer 514 includes a number of discrete grains in vertical correspondence with the grains of the recording layer 512.


The other layers of the damped magnetic media 504 can function, and be made of the same materials, as described above for the damped magnetic media 204 of FIG. 2a.



FIG. 4 is a flowchart of a process 400 for forming a damped magnetic media with a doped capping layer positioned on the recording layer in accordance with one embodiment of the invention. In particular embodiments, the process 400 can be used to form the damped magnetic media of FIGS. 2a and 2b. The process first provides (402) a heat sink layer. In some embodiments, the heat sink layer is formed on a substrate (e.g., soft magnetic underlayer). The process then provides (404) a growth layer on the heat sink layer. In some embodiments, the process also provides a thermal resistor layer on the heat sink layer. In such case, the growth layer is formed on the thermal resistor layer.


The process then provides (406) a magnetic recording layer on the growth layer, where the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer. The process then provides (408) a capping magnetic recording layer on the magnetic recording layer, where the capping recording layer includes a first material configured to increase a damping constant of the capping recording layer to a first preselected level. In some embodiments, the process also provides an exchange coupling layer on the magnetic recording layer. In such case, the capping magnetic recording layer is formed on the exchange coupling layer.


In a number of embodiments, the process can use suitable deposition processes (e.g., sputtered deposition and/or other physical vapor deposition methods known in the art) known in the art to provide the various layers.


In one embodiment, the process can perform the sequence of actions in a different order. In another embodiment, the process can skip one or more of the actions. In other embodiments, one or more of the actions are performed simultaneously. In some embodiments, additional actions can be performed.



FIG. 5 is a flowchart of a process 500 for forming a damped magnetic media with a doped underlayer positioned beneath the recording layer in accordance with one embodiment of the invention. In particular embodiments, the process 500 can be used to form the damped magnetic media of FIGS. 3a and 3b. The process first provides (502) a heat sink layer. In some embodiments, the heat sink layer is formed on a substrate (e.g., soft magnetic underlayer). The process then provides (504) a growth layer on the heat sink layer. In some embodiments, the process also provides a thermal resistor layer on the heat sink layer. In such case, the growth layer is formed on the thermal resistor layer.


The process then provides (506) a magnetic recording underlayer on the growth layer, where the underlayer includes a first material configured to increase a damping constant of the underlayer to a first preselected level. The process then provides (508) a magnetic recording layer on the underlayer, where the growth layer and the underlayer are configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer. In some embodiments, the process also provides a capping layer on the magnetic recording layer. In some embodiments, the magnetic recording layer includes a number of discrete magnetic grains separated by gaps. In one such case, the process also deposits additional amounts of the first material in the gaps in the recording layer, thereby doping the recording layer in addition to the underlayer.


In a number of embodiments, the process can use suitable deposition processes (e.g., sputtered deposition and/or other physical vapor deposition methods known in the art) known in the art to provide the various layers.


In one embodiment, the process can perform the sequence of actions in a different order. In another embodiment, the process can skip one or more of the actions. In other embodiments, one or more of the actions are performed simultaneously. In some embodiments, additional actions can be performed.


While the above description contains many specific embodiments of the invention, these should not be construed as limitations on the scope of the invention, but rather as examples of specific embodiments thereof. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their equivalents.

Claims
  • 1. A magnetic media structure for heat assisted magnetic recording, the media structure comprising: a heat sink layer;a growth layer on the heat sink layer;a magnetic recording layer on the growth layer, wherein the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer; anda capping magnetic recording layer on the magnetic recording layer, the capping magnetic recording layer comprising a first material configured to increase a damping constant of the capping recording layer to a first preselected level,wherein the magnetic recording layer comprises a plurality of discrete magnetic grains separated by a plurality of gaps; andwherein the plurality of gaps are at least partially filled with the first material.
  • 2. The media structure of claim 1, wherein the first material comprises a rare earth dopant.
  • 3. The media structure of claim 2, wherein the rare earth dopant comprises Ho.
  • 4. The media structure of claim 2, wherein the rare earth dopant comprises a material selected from the group consisting of Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Hf.
  • 5. The media structure of claim 1, wherein the capping magnetic recording layer comprises a substantially continuous structure.
  • 6. The media structure of claim 1: wherein the magnetic recording layer comprises a plurality of discrete magnetic grains; andwherein the capping magnetic recording layer comprises a plurality of grains in vertical correspondence with the plurality of discrete magnetic grains.
  • 7. The media structure of claim 1, further comprising an exchange coupling layer positioned between the capping magnetic recording layer and the magnetic recording layer.
  • 8. The media structure of claim 1, further comprising a thermal resistor layer positioned between the heat sink layer and the growth layer.
  • 9. The media structure of claim 1: wherein the magnetic recording layer comprises FePt;wherein the growth layer comprises MgO; andwherein the capping magnetic recording layer comprises a material selected from the group consisting of Fe, Pt, Co, Cr, Ni, and combinations thereof.
  • 10. The media structure of claim 1, further comprising an underlayer comprising a soft magnetic material, wherein the heat sink layer is positioned on the soft underlayer.
  • 11. The media structure of claim 1, wherein the first material increases a damping constant of the capping recording layer to a first preselected level.
  • 12. A magnetic media structure for heat assisted magnetic recording, the media structure comprising: a heat sink layer;a growth layer on the heat sink layer;a magnetic recording underlayer on the growth layer, the underlayer comprising a first material configured to increase a damping constant of the underlayer to a first preselected level; anda magnetic recording layer on the underlayer, wherein the growth layer and the underlayer are configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer,wherein the magnetic recording layer comprises a plurality of discrete magnetic grains separated by a plurality of gaps; andwherein the plurality of gaps are at least partially filled with the first material.
  • 13. The media structure of claim 12, wherein the first material comprises a rare earth dopant.
  • 14. The media structure of claim 13, wherein the rare earth dopant comprises Ho.
  • 15. The media structure of claim 13, wherein the rare earth dopant comprises a material selected from the group consisting of Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Hf.
  • 16. The media structure of claim 12, wherein the underlayer comprises a substantially continuous structure.
  • 17. The media structure of claim 12: wherein the magnetic recording layer comprises a plurality of discrete magnetic grains; andwherein the underlayer comprises a plurality of grains in vertical correspondence with the plurality of discrete magnetic grains.
  • 18. The media structure of claim 12, further comprising a thermal resistor layer positioned between the heat sink layer and the growth layer.
  • 19. The media structure of claim 12: wherein the magnetic recording layer comprises FePt;wherein the growth layer comprises MgO; andwherein the underlayer comprises a material selected from the group consisting of Fe, Pt, Co, Cr, Ni, and combinations thereof.
  • 20. The media structure of claim 12, further comprising a second underlayer comprising a soft magnetic material, wherein the heat sink layer is on the second underlayer.
  • 21. The media structure of claim 12, wherein the first material increases a damping constant of the capping recording layer to a first preselected level.
  • 22. A method for increasing a damping constant of a magnetic media structure for heat assisted magnetic recording, the method comprising: providing a heat sink layer;providing a growth layer on the heat sink layer;providing a magnetic recording layer on the growth layer, wherein the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer; andproviding a capping magnetic recording layer on the magnetic recording layer, the capping recording layer comprising a first material configured to increase a damping constant of the capping recording layer to a first preselected level,wherein the magnetic recording layer comprises a plurality of discrete magnetic grains separated by a plurality of gaps; andwherein the plurality of gaps are at least partially filled with the first material.
  • 23. The method of claim 22, wherein the first material comprises a rare earth dopant.
  • 24. The method of claim 23, wherein the rare earth dopant comprises Ho.
  • 25. The method of claim 23, wherein the rare earth dopant comprises a material selected from the group consisting of Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Hf.
  • 26. The method of claim 22, wherein the capping magnetic recording layer comprises a substantially continuous structure.
  • 27. The method of claim 22: wherein the magnetic recording layer comprises a plurality of discrete magnetic grains; andwherein the capping magnetic recording layer comprises a plurality of grains in vertical correspondence with the plurality of discrete magnetic grains.
  • 28. The method of claim 22, further comprising an exchange coupling layer positioned between the capping magnetic recording layer and the magnetic recording layer.
  • 29. The method of claim 22, further comprising a thermal resistor layer positioned between the heat sink layer and the growth layer.
  • 30. The method of claim 22: wherein the magnetic recording layer comprises FePt;wherein the growth layer comprises MgO; andwherein the capping magnetic recording layer comprises a material selected from the group consisting of Fe, Pt, Co, Cr, Ni, and combinations thereof.
  • 31. The method of claim 22, further comprising an underlayer comprising a soft magnetic material, wherein the heat sink layer is positioned on the soft underlayer.
  • 32. The method of claim 22, wherein the first material increases a damping constant of the capping recording layer to a first preselected level.
  • 33. A method for increasing a damping constant of a magnetic media structure for heat assisted magnetic recording, the method comprising: providing a heat sink layer;providing a growth layer on the heat sink layer;providing a magnetic recording underlayer on the growth layer, the underlayer comprising a first material configured to increase a damping constant of the underlayer to a first preselected level; andproviding a magnetic recording layer on the underlayer, wherein the growth layer and the underlayer are configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer,wherein the magnetic recording layer comprises a plurality of discrete magnetic grains separated by a plurality of gaps; andwherein the plurality of gaps are at least partially filled with the first material.
  • 34. The method of claim 33, wherein the first material comprises a rare earth dopant.
  • 35. The method of claim 34, wherein the rare earth dopant comprises Ho.
  • 36. The method of claim 34, wherein the rare earth dopant comprises a material selected from the group consisting of Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Hf.
  • 37. The method of claim 33, wherein the underlayer comprises a substantially continuous structure.
  • 38. The method of claim 33: wherein the magnetic recording layer comprises a plurality of discrete magnetic grains; andwherein the underlayer comprises a plurality of grains in vertical correspondence with the plurality of discrete magnetic grains.
  • 39. The method of claim 33, further comprising a thermal resistor layer positioned between the heat sink layer and the growth layer.
  • 40. The method of claim 33: wherein the magnetic recording layer comprises FePt;wherein the growth layer comprises MgO; andwherein the underlayer comprises a material selected from the group consisting of Fe, Pt, Co, Cr, Ni, and combinations thereof.
  • 41. The method of claim 33, further comprising a second underlayer comprising a soft magnetic material, wherein the heat sink layer is on the second underlayer.
  • 42. The method of claim 33, wherein the first material increases a damping constant of the capping recording layer to a first preselected level.
US Referenced Citations (343)
Number Name Date Kind
4833560 Doyle May 1989 A
6013161 Chen et al. Jan 2000 A
6063248 Bourez et al. May 2000 A
6068891 O'Dell et al. May 2000 A
6086730 Liu et al. Jul 2000 A
6099981 Nishimori Aug 2000 A
6103404 Ross et al. Aug 2000 A
6117499 Wong et al. Sep 2000 A
6136403 Prabhakara et al. Oct 2000 A
6143375 Ross et al. Nov 2000 A
6145849 Bae et al. Nov 2000 A
6146737 Malhotra et al. Nov 2000 A
6149696 Jia Nov 2000 A
6150015 Bertero et al. Nov 2000 A
6156404 Ross et al. Dec 2000 A
6159076 Sun et al. Dec 2000 A
6164118 Suzuki et al. Dec 2000 A
6200441 Gornicki et al. Mar 2001 B1
6204995 Hokkyo et al. Mar 2001 B1
6206765 Sanders et al. Mar 2001 B1
6210819 Lal et al. Apr 2001 B1
6216709 Fung et al. Apr 2001 B1
6221119 Homola Apr 2001 B1
6248395 Homola et al. Jun 2001 B1
6261681 Suekane et al. Jul 2001 B1
6270885 Hokkyo et al. Aug 2001 B1
6274063 Li et al. Aug 2001 B1
6283838 Blake et al. Sep 2001 B1
6287429 Moroishi et al. Sep 2001 B1
6290573 Suzuki Sep 2001 B1
6299947 Suzuki et al. Oct 2001 B1
6303217 Malhotra et al. Oct 2001 B1
6309765 Suekane et al. Oct 2001 B1
6358636 Yang et al. Mar 2002 B1
6362452 Suzuki et al. Mar 2002 B1
6363599 Bajorek Apr 2002 B1
6365012 Sato et al. Apr 2002 B1
6381090 Suzuki et al. Apr 2002 B1
6381092 Suzuki Apr 2002 B1
6387483 Hokkyo et al. May 2002 B1
6391213 Homola May 2002 B1
6395349 Salamon May 2002 B1
6403919 Salamon Jun 2002 B1
6408677 Suzuki Jun 2002 B1
6426157 Hokkyo et al. Jul 2002 B1
6429984 Alex Aug 2002 B1
6482330 Bajorek Nov 2002 B1
6482505 Bertero et al. Nov 2002 B1
6500567 Bertero et al. Dec 2002 B1
6528124 Nguyen Mar 2003 B1
6548821 Treves et al. Apr 2003 B1
6552871 Suzuki et al. Apr 2003 B2
6565719 Lairson et al. May 2003 B1
6566674 Treves et al. May 2003 B1
6571806 Rosano et al. Jun 2003 B2
6628466 Alex Sep 2003 B2
6649254 Victora et al. Nov 2003 B1
6664503 Hsieh et al. Dec 2003 B1
6670055 Tomiyasu et al. Dec 2003 B2
6682807 Lairson et al. Jan 2004 B2
6683754 Suzuki et al. Jan 2004 B2
6730420 Bertero et al. May 2004 B1
6743528 Suekane et al. Jun 2004 B2
6759138 Tomiyasu et al. Jul 2004 B2
6778353 Harper Aug 2004 B1
6795274 Hsieh et al. Sep 2004 B1
6830824 Kikitsu et al. Dec 2004 B2
6855232 Jairson et al. Feb 2005 B2
6857937 Bajorek Feb 2005 B2
6893748 Bertero et al. May 2005 B2
6899959 Bertero et al. May 2005 B2
6916558 Umezawa et al. Jul 2005 B2
6939120 Harper Sep 2005 B1
6946191 Morikawa et al. Sep 2005 B2
6967798 Homola et al. Nov 2005 B2
6972135 Homola Dec 2005 B2
7004827 Suzuki et al. Feb 2006 B1
7006323 Suzuki Feb 2006 B1
7016154 Nishihira Mar 2006 B2
7019924 McNeil et al. Mar 2006 B2
7045215 Shimokawa May 2006 B2
7070870 Bertero et al. Jul 2006 B2
7090934 Hokkyo et al. Aug 2006 B2
7099112 Harper Aug 2006 B1
7105241 Shimokawa et al. Sep 2006 B2
7119990 Bajorek et al. Oct 2006 B2
7147790 Wachenschwanz et al. Dec 2006 B2
7161753 Wachenschwanz et al. Jan 2007 B2
7166319 Ishiyama Jan 2007 B2
7166374 Suekane et al. Jan 2007 B2
7169487 Kawai et al. Jan 2007 B2
7174775 Ishiyama Feb 2007 B2
7179549 Malhotra et al. Feb 2007 B2
7184139 Treves et al. Feb 2007 B2
7196860 Alex Mar 2007 B2
7199977 Suzuki et al. Apr 2007 B2
7208236 Morikawa et al. Apr 2007 B2
7220500 Tomiyasu et al. May 2007 B1
7229266 Harper Jun 2007 B2
7239970 Treves et al. Jul 2007 B2
7252897 Shimokawa et al. Aug 2007 B2
7277254 Shimokawa et al. Oct 2007 B2
7281920 Homola et al. Oct 2007 B2
7292329 Treves et al. Nov 2007 B2
7301726 Suzuki Nov 2007 B1
7302148 Treves et al. Nov 2007 B2
7305119 Treves et al. Dec 2007 B2
7314404 Singh et al. Jan 2008 B2
7320584 Harper et al. Jan 2008 B1
7329114 Harper et al. Feb 2008 B2
7354664 Jiang et al. Apr 2008 B1
7375362 Treves et al. May 2008 B2
7420886 Tomiyasu et al. Sep 2008 B2
7425719 Treves et al. Sep 2008 B2
7471484 Wachenschwanz et al. Dec 2008 B2
7498062 Calcaterra et al. Mar 2009 B2
7531485 Hara et al. May 2009 B2
7537846 Ishiyama et al. May 2009 B2
7549209 Wachenschwanz et al. Jun 2009 B2
7569490 Staud Aug 2009 B2
7597792 Homola et al. Oct 2009 B2
7597973 Ishiyama Oct 2009 B2
7608193 Wachenschwanz et al. Oct 2009 B2
7632087 Homola Dec 2009 B2
7656615 Wachenschwanz et al. Feb 2010 B2
7682546 Harper Mar 2010 B2
7684152 Suzuki et al. Mar 2010 B2
7686606 Harper et al. Mar 2010 B2
7686991 Harper Mar 2010 B2
7695833 Ishiyama Apr 2010 B2
7722968 Ishiyama May 2010 B2
7733605 Suzuki et al. Jun 2010 B2
7736768 Ishiyama Jun 2010 B2
7755861 Li et al. Jul 2010 B1
7758732 Calcaterra et al. Jul 2010 B1
7833639 Sonobe et al. Nov 2010 B2
7833641 Tomiyasu et al. Nov 2010 B2
7910159 Jung Mar 2011 B2
7911736 Bajorek Mar 2011 B2
7924519 Lambert Apr 2011 B2
7944165 O'Dell May 2011 B1
7944643 Jiang et al. May 2011 B1
7955723 Umezawa et al. Jun 2011 B2
7983003 Sonobe et al. Jul 2011 B2
7993497 Moroishi et al. Aug 2011 B2
7993765 Kim et al. Aug 2011 B2
7998912 Chen et al. Aug 2011 B2
8002901 Chen et al. Aug 2011 B1
8003237 Sonobe et al. Aug 2011 B2
8012920 Shimokawa Sep 2011 B2
8038863 Homola Oct 2011 B2
8057926 Ayama et al. Nov 2011 B2
8062778 Suzuki et al. Nov 2011 B2
8064156 Suzuki et al. Nov 2011 B1
8076013 Sonobe et al. Dec 2011 B2
8092931 Ishiyama et al. Jan 2012 B2
8100685 Harper et al. Jan 2012 B1
8101054 Chen et al. Jan 2012 B2
8125723 Nichols et al. Feb 2012 B1
8125724 Nichols et al. Feb 2012 B1
8137517 Bourez Mar 2012 B1
8142916 Umezawa et al. Mar 2012 B2
8163093 Chen et al. Apr 2012 B1
8171949 Lund et al. May 2012 B1
8173282 Sun et al. May 2012 B1
8178480 Hamakubo et al. May 2012 B2
8206789 Suzuki Jun 2012 B2
8218260 Iamratanakul et al. Jul 2012 B2
8228636 Lomakin et al. Jul 2012 B2
8247095 Champion et al. Aug 2012 B2
8257783 Suzuki et al. Sep 2012 B2
8298609 Liew et al. Oct 2012 B1
8298689 Sonobe et al. Oct 2012 B2
8309239 Umezawa et al. Nov 2012 B2
8316668 Chan et al. Nov 2012 B1
8331056 O'Dell Dec 2012 B2
8351309 Kanbe et al. Jan 2013 B2
8354618 Chen et al. Jan 2013 B1
8367228 Sonobe et al. Feb 2013 B2
8383209 Ayama Feb 2013 B2
8394243 Jung et al. Mar 2013 B1
8397751 Chan et al. Mar 2013 B1
8399051 Hellwig et al. Mar 2013 B1
8399809 Bourez Mar 2013 B1
8402638 Treves et al. Mar 2013 B1
8404056 Chen et al. Mar 2013 B1
8404369 Ruffini et al. Mar 2013 B2
8404370 Sato et al. Mar 2013 B2
8406918 Tan et al. Mar 2013 B2
8414966 Yasumori et al. Apr 2013 B2
8425975 Ishiyama Apr 2013 B2
8431257 Kim et al. Apr 2013 B2
8431258 Onoue et al. Apr 2013 B2
8453315 Kajiwara et al. Jun 2013 B2
8488276 Jung et al. Jul 2013 B1
8491800 Dorsey Jul 2013 B1
8492009 Homola et al. Jul 2013 B1
8492011 Itoh et al. Jul 2013 B2
8496466 Treves et al. Jul 2013 B1
8517364 Crumley et al. Aug 2013 B1
8517657 Chen et al. Aug 2013 B2
8524052 Tan et al. Sep 2013 B1
8530065 Chernyshov et al. Sep 2013 B1
8542569 Kanbe et al. Sep 2013 B2
8546000 Umezawa Oct 2013 B2
8551253 Na'im et al. Oct 2013 B2
8551627 Shimada et al. Oct 2013 B2
8556566 Suzuki et al. Oct 2013 B1
8559131 Masuda et al. Oct 2013 B2
8562748 Chen et al. Oct 2013 B1
8565050 Bertero et al. Oct 2013 B1
8570844 Yuan et al. Oct 2013 B1
8576672 Peng et al. Nov 2013 B1
8580410 Onoue Nov 2013 B2
8584687 Chen et al. Nov 2013 B1
8591709 Lim et al. Nov 2013 B1
8592061 Onoue et al. Nov 2013 B2
8596287 Chen et al. Dec 2013 B1
8597723 Jung et al. Dec 2013 B1
8603649 Onoue Dec 2013 B2
8603650 Sonobe et al. Dec 2013 B2
8605388 Yasumori et al. Dec 2013 B2
8605555 Chernyshov et al. Dec 2013 B1
8608147 Yap et al. Dec 2013 B1
8609263 Chernyshov et al. Dec 2013 B1
8619381 Moser et al. Dec 2013 B2
8623528 Umezawa et al. Jan 2014 B2
8623529 Suzuki Jan 2014 B2
8634155 Yasumori et al. Jan 2014 B2
8658003 Bourez Feb 2014 B1
8658292 Mallary et al. Feb 2014 B1
8665541 Saito Mar 2014 B2
8668953 Buechel-Rimmel Mar 2014 B1
8674327 Poon et al. Mar 2014 B1
8685214 Moh et al. Apr 2014 B1
8696404 Sun et al. Apr 2014 B2
8711499 Desai et al. Apr 2014 B1
8743666 Bertero et al. Jun 2014 B1
8758912 Srinivasan et al. Jun 2014 B2
8787124 Chernyshov et al. Jul 2014 B1
8787130 Yuan et al. Jul 2014 B1
8791391 Bourez Jul 2014 B2
8795765 Koike et al. Aug 2014 B2
8795790 Sonobe et al. Aug 2014 B2
8795857 Ayama et al. Aug 2014 B2
20020060883 Suzuki May 2002 A1
20030022024 Wachenschwanz Jan 2003 A1
20040022387 Weikle Feb 2004 A1
20040132301 Harper et al. Jul 2004 A1
20040137277 Iwasaki et al. Jul 2004 A1
20040202793 Harper et al. Oct 2004 A1
20040202865 Homola et al. Oct 2004 A1
20040209123 Bajorek et al. Oct 2004 A1
20040209470 Bajorek Oct 2004 A1
20050036223 Wachenschwanz et al. Feb 2005 A1
20050129985 Oh et al. Jun 2005 A1
20050142990 Homola Jun 2005 A1
20050150862 Harper et al. Jul 2005 A1
20050151282 Harper et al. Jul 2005 A1
20050151283 Bajorek et al. Jul 2005 A1
20050151300 Harper et al. Jul 2005 A1
20050155554 Saito Jul 2005 A1
20050167867 Bajorek et al. Aug 2005 A1
20050263401 Olsen et al. Dec 2005 A1
20050274221 Ziani et al. Dec 2005 A1
20060147758 Jung et al. Jul 2006 A1
20060154110 Hohlfeld et al. Jul 2006 A1
20060181697 Treves et al. Aug 2006 A1
20060207890 Staud Sep 2006 A1
20070003792 Covington et al. Jan 2007 A1
20070070549 Suzuki et al. Mar 2007 A1
20070245909 Homola Oct 2007 A1
20080075845 Sonobe et al. Mar 2008 A1
20080093760 Harper et al. Apr 2008 A1
20090061259 Lee et al. Mar 2009 A1
20090117408 Umezawa et al. May 2009 A1
20090136784 Suzuki et al. May 2009 A1
20090155627 Berger et al. Jun 2009 A1
20090169922 Ishiyama Jul 2009 A1
20090191331 Umezawa et al. Jul 2009 A1
20090202866 Kim et al. Aug 2009 A1
20090311557 Onoue et al. Dec 2009 A1
20100073813 Dai et al. Mar 2010 A1
20100124672 Thangaraj et al. May 2010 A1
20100143752 Ishibashi et al. Jun 2010 A1
20100190035 Sonobe et al. Jul 2010 A1
20100196619 Ishiyama Aug 2010 A1
20100196740 Ayama et al. Aug 2010 A1
20100209601 Shimokawa et al. Aug 2010 A1
20100215992 Horikawa et al. Aug 2010 A1
20100232065 Suzuki et al. Sep 2010 A1
20100247965 Onoue Sep 2010 A1
20100261039 Itoh et al. Oct 2010 A1
20100279151 Sakamoto et al. Nov 2010 A1
20100300884 Homola et al. Dec 2010 A1
20100304186 Shimokawa Dec 2010 A1
20100309577 Gao et al. Dec 2010 A1
20110097603 Onoue Apr 2011 A1
20110097604 Onoue Apr 2011 A1
20110171495 Tachibana et al. Jul 2011 A1
20110206947 Tachibana et al. Aug 2011 A1
20110212346 Onoue et al. Sep 2011 A1
20110223446 Onoue et al. Sep 2011 A1
20110244119 Umezawa et al. Oct 2011 A1
20110299194 Aniya et al. Dec 2011 A1
20110311841 Saito et al. Dec 2011 A1
20120069466 Okamoto et al. Mar 2012 A1
20120070692 Sato et al. Mar 2012 A1
20120077060 Ozawa Mar 2012 A1
20120127599 Shimokawa et al. May 2012 A1
20120127601 Suzuki et al. May 2012 A1
20120129009 Sato et al. May 2012 A1
20120140359 Tachibana Jun 2012 A1
20120141833 Umezawa et al. Jun 2012 A1
20120141835 Sakamoto Jun 2012 A1
20120148875 Hamakubo et al. Jun 2012 A1
20120156523 Seki et al. Jun 2012 A1
20120164488 Shin et al. Jun 2012 A1
20120170152 Sonobe et al. Jul 2012 A1
20120171369 Koike et al. Jul 2012 A1
20120175243 Fukuura et al. Jul 2012 A1
20120189872 Umezawa et al. Jul 2012 A1
20120194942 Hohlfeld et al. Aug 2012 A1
20120196049 Azuma et al. Aug 2012 A1
20120207919 Sakamoto et al. Aug 2012 A1
20120225217 Itoh et al. Sep 2012 A1
20120251842 Yuan et al. Oct 2012 A1
20120251845 Wang et al. Oct 2012 A1
20120251846 Desai et al. Oct 2012 A1
20120276417 Shimokawa et al. Nov 2012 A1
20120308722 Suzuki et al. Dec 2012 A1
20130040167 Alagarsamy et al. Feb 2013 A1
20130071694 Srinivasan et al. Mar 2013 A1
20130165029 Sun et al. Jun 2013 A1
20130175252 Bourez Jul 2013 A1
20130216865 Yasumori et al. Aug 2013 A1
20130230647 Onoue et al. Sep 2013 A1
20130288079 Chang et al. Oct 2013 A1
20130314815 Yuan et al. Nov 2013 A1
20140011054 Suzuki Jan 2014 A1
20140044992 Onoue Feb 2014 A1
20140050843 Yi et al. Feb 2014 A1
20140151360 Landdell et al. Jun 2014 A1
Non-Patent Literature Citations (5)
Entry
Bailey, William, Pavel Kabos, Frederick Mancoff and Stephen Russek, Control of Magnetization Dynamics in Ni18Fe19 Thin Films Through the Use of Rare-Earth Dopants, IEEE Transactions of Magnetics, vol. 37, No. 4, Jul. 2011, pp. 1749-1754.
Krivoski, Pavol, Sangita S. Kalarickal, Nan Mo, Stella We and Carl E. Patton, “Ferromagnetic Resonance and Damping in Granular Co—Cr Films with Perpendicular Anisotropy,” Applied Physics Letters 95, American Institute of Physics, May 2009, 3 pages.
Nedo and Hitachi Presentation.
Nedo, Hitachi and Hitachi GST, “Microwave-Assisted Magnetic Recording for Net Gen HDD,” StorageNewsletter.com, Nov. 2010.
Zhu, Jiang-Gang, Xiaochun Zhu and Yuhui Tang, “Microwave Assisted Magnetic Recording,” IEEE Transaction on Magnetics, vol. 44, No. 1, January, pp. 125-131.