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Exchange-coupled media for magnetic recording

Keywords:

V.G. Shadrov – Ph.D. (Phys.-Math.), Leading Research Scientist, Scientific-Practical Materials Research Centre

A.V. Boltushkin – Ph.D. (Phys.-Math.), Leading Research Scientist, Scientific-Practical Materials Research Centre

A.E. Dmitrieva – Junior Research Scientist, Scientific-Practical Materials Research Centre
E-mail: nemtsevich@ifttp.bas-net.by


Driven by the need for worldwide data storage, increase in areal density is crucial for the hard disc drive industry. A signal-to-noise, thermal stability, and writability tradeoff limits the ability to continue to scale traditional magnetic recording technology to higher storage densities. As a solution, heat-assisted magnetic recording, bit patterned magnetic media, exchange-coupled media etc. are proposed. In particular, exchange-coupled media composed of hard and soft magnetic layers coupled by an exchange interaction allow to reduce the switching field without decreasing thermal stability and achieve areal density up to 10 Tb/inch2.
In the present paper basic exchange-coupled perpendicular media parameters, high anisotropy materials and new alternatives for the next generation of magnetic recording media are analyzed. The possibility of achieving 5…10 Tb/inch2 in graded media with continuously varying magnetic anisotropy constant and a grain size of 3,2 nm has been shown as well as a perspective of combining exchange-coupled media with high degree of SiO2 segregation and coupled granular continuous media with very thin exchange coupled continuous layer. In evaluating exchange-coupled structures perspectives one should also take into consideration a possibility of their utilization in heat-assisted magnetic recording and in bit-patterned media. In particular, for improving heat-assisted magnetic media parameters, namely, Curie temperature and writing temperature decreasing, exchange-spring FePt/FeRh structure and exchange-coupled multilayer structure with different layer Curie temperatures and close values of coercivity are proposed. Upon heating FePt/FeRh structure beyond the Neel temperature, FeRh alloy (50:50) becomes ferromagnetic and assists the switching of the hard FePt layer via an exchange-spring effect. It was also shown that exchange-coupled bit-patterned media are more simple technologically and characterized by switching field distribution decreasing and significant bit error rate improvement in compare with granular media. The analysis made allows to conclude that areal density extensions beyond 10 Tb/inch2 will likely require the combination of heat-assisted magnetic recording and bit patterned magnetic recording technologies and/or exchange coupled structures.

References:
  1. Stamps R., Breitkreuts S., Akerman J., Chumak A. The 2014 magnetism roadmap // J. Phys. D.: Appl. Phys. 2014. V. 47. P. 33301-1-28.
  2. Richter H.J. The transition from longitudinal to perpendicular recording // J. Phys. D.: Appl. Phys. 2007. V. 40. P. R149–R177.
  3. Plumer M.L., Cain W.C. New paradigms in magnetic recording // Physics in Canada. 2011. V. 67. P. 25–29.
  4. Shadrov V.G., Dmitrieva A.Je., Boltushkin A.V. Superparamagnitnyj predel i termostabil'nost' sred magnitnoj zapisi // Uspehi sovremennoj radiojelektroniki. 2015. № 12. S. 67–76.
  5. Weller D., Moser A. Thermal effect limits in ultrahigh-density magnetic recording // IEEE Trans. Magn. 1999. V. 35. P. 4423–4439.
  6. Terris B.D., Thomson T. Nanofabricated and self-assembled magnetic structures as data storage media // J. Phys. D: Appl. Phys. 2005. V. 38. P. R. 199–222.
  7. Kryder M.H., Gage E.C., McDaniel T.W., Challener W.A., Rottmayer R.E., Ju G., Hsia Y.-T., Erden M.F. Heat assisted magnetic recording // Proc. IEEE. 2008. V. 96. P. 1810–1835.
  8. Zhu J. G., Zhu X., Tang Y. Microwave assisted magnetic recording // IEEE Trans. Magn. 2008. V. 44. P. 125–131.
  9. Suess D., Schrefl T., Fahler S., Kirschner M., Hrkac G., Dorfbauer F., Fidler J. Exchange spring media for perpendicular recording // Appl. Phys. Lett. 2005. V. 87. P. 012504-1-3.
  10. Victora R. H., Shen X. Exchange coupled composite media for perpendi-cular magnetic recording // IEEE Trans. Magn. 2005. V. 41. P. 2828–2833.
  11. Zou Y.Y., Wang J.P., Hee C.H., Chong T.C. Tilted media in a perpendi-cular recording system for high areal density recording // Appl. Phys. Lett. 2003. V. 82. P. 2473–2475.
  12. Suess D., Fuger M., Abert C., Bruckner F., Vogler C. Superior bit error rate and jitter due to improved switching field distribution in exchange spring magnetic recording media // Sci. Rep. 2016. V. 6. P. 27048-1-12.
  13. Weller D., Parker G., Mosendz O., Champion E., Stipe B., Wang X., Klemmer T., Ju G., Ajan A. A HAMR media technology roadmap to an areal density of 4 Tb/in2 // IEEE Trans. Magn. 2014. V. 50. P. 3100108-1-8.
  14. Zhou N., Traverso L.M., Xu X. Power delivery and self-heating in nanoscale near-field transducer for heat-assisted magnetic recording // Nanotechnology. 2015. V. 26. P. 134001-1-7.
  15. Kikitsu A. Prospects for bit patterned media for high-density magnetic recording // J. Magn. Magn. Mater. 2009. V. 321. P. 526–530.
  16. Wang F., Xu X.-H. Writability issues in high-anisotropy perpendicular magnetic recording media // Chin. Phys. B. 2014. V. 23. P.036802-1-12.
  17. Gao K.-Z., Bertram H.N. Write field analysis in perpendicular recording using 3D micro-magnetic simulation // J. Appl. Phys. 2002. V. 91. P. 8369–8371.
  18. Sonobe Y., Weller D., Ikeda Y., Takano K., Schabes M., Zeltzer G., Do H., Yen B., Best M. Coupled granular/continuous medium for thermally stable perpendicular magnetic recording // J. Magn. Magn. Mater. 2001. V. 235. P. 424–428.
  19. Sonobe Y., Muraoka H.,  Miura K., Nakamura Y., Takano K., Moser A., Do H., Yen B., Ikeda Y., Supper N., Weresin W. Thermally stable CGC perpendicular recording media with Pt-rich CoPtCr and thin Pt layers // IEEE Trans. Magn. 2002. V. 38. P. 2006–2011.
  20. Yasumori J., Sonobe Y., Greaves S.J., Tham K.K. Approach to High-Density Recording Using CGC Structure // IEEE Trans. Magn. 2009. V. 45. P. 850–855.
  21. Sonobe Y., Weller D., Ikeda Y., Schabes M.E., Takano K., Zeltzer G., Yen B.K., Best M.E., Graves S.J., Muraoka H., Nakamura Y. Thermal stability and SNR of coupled granular/continuous media // IEEE Trans. Magn. 2001. V. 37. P. 1667–1670.
  22. Sonobe Y., Muraoka H., Miura K., Nakamura Y., Takano K., Do H., Moser A., Yen B. K., Ikeda Y., Supper N. Coupled granular/continuous perpendicular recording media with soft magnetic underlayer // J. Appl. Phys. 2002. V. 91. P. 8055–8057.
  23. Shimatsu T., Muraoka H., Nakamura Y., Sonobe Y., Satodate Y., Muramatsu K., Watanabe I. High thermal stability in CoPrTb/CoCrTa composite perpendicular media // J. Appl. Phys. 2002. V. 91. P. 8061–8063.
  24. Yasumori J., Miura K., Muraoka H., Sonobe Y., Wago K. SNR improvement by intergranular exchange coupling in CGC perpendicular magnetic recording media // J. Magn. Magn. Mater. 2008. V. 320. Р. 3079–3082.
  25. Sonobe Y., Tham K. K., Wu J., Umezava T., Takatsu C., Dumaya J.A.H., Onoue T., Leo P.Y., Liau M. CGC perpendicular recording media with CoCrPt-SiO2 alloy as granular layer // IEEE Trans. Magn. 2006. V. 42. P. 2351–2353.
  26. Tham K.K., Sonobe Y., Wago K. Magnetic and read-write properties of CGC perpendicular recording media and magnetization reversal process // IEEE Trans. Magn. 2007. V. 43. P. 671–675.
  27. Sonobe Y., Tham K.K., UmezawaA T., Takatsu C., Dumaya J.A., Leo P.Y. Effect of continuous layer in CGC perpendicular recording media // J. Magn. Magn. Mater. 2006. V. 303. P. 292–295.
  28. Gavrila H. Coupled granular/continuous media for perpendicular magnetic recording // Proc. Roman. Acad. A. 2010. V. 11. P. 41–46.
  29. Miura K., Muraoka H., Sonobe Y., Nakamura Y. Jitter reduction by using a continuous hard-magnetic layer for perpendicular recording media // IEEE Trans. Magn. 2002. V. 38. P. 2054–2056.
  30. Goodman A.M., Muraoka H., Greaves S.J., Miura K., Sonobe Y., Nakamura Y. Effect of intergranular exchange coupling on transition irregularity in coupled granular/continuous perpendicular media // IEEE Trans. Magn. 2003. V. 39. P. 685–690.
  31. Goodman A.M., Greaves S.J., Sonobe Y., Muraoka H., Nakamura Y. Simulations of magnetic recording in coupled granular/continuous perpendicular media with random pinning sites // IEEE Trans. Magn. 2002. V. 38. P. 2051–2053.
  32. Piramanayagam S.N., Srinvasan K. Recording media research for future hard disk drives // J. Magn. Magn. Mater. 2009. V. 321. P. 485–494.
  33. Muraoka H., Sonobe Y., Miura K., Goodman A.M., Nakamura Y. Analysis on magnetization transition of CGC perpendicular media // IEEE Trans. Magn. 2002. V. 38. P. 1632–1636.
  34. Wang J.P., Zou Y.Y., Hee C., Chong T., Zheng Y.F. Approaches to tilted magnetic recording for extremely high areal density// IEEE Trans. Magn. 2003. V. 39. № 4. P. 1930–1935.
  35. Yan S-S., Barnard J.A., Xu F.T., Weston J.L., Zangari G. Critical dimension of the transition from single switching to an exchange spring process in hard/soft exchange-coupled bilayers // Phys. Rev.B, Cond. Matter. 2001. V. 64. P. 184403-1-6.
  36. Casoli F., Albertini F., Fabbrici S., Bocchi C., Nasi L., Ciprian R., Pareti L. Exchange-coupled FePt/Fe bilayers with perpendicular magnetization// IEEE Trans. Magn. 2005. V. 41. P. 3877–3879.
  37. Casoli F., Albertini F, Nasi L., Fabbrici S., Cabassi R, Bolzoni F., Bocchi C. Strong coercivity reduction in perpendicular FePt/Fe bilayers due to hard/soft coupling // Appl. Phys. Lett. 2008. V. 92. P. 142506-1-3.
  38. Dobin A.Y., Richter H.J. Domain wall assisted magnetic recording // J. Appl. Phys. 2007. V. 101. P. 09K108-1-4.
  39. Goll D., Macke S., Kronmuller H. Exchange coupled composite layers for magnetic recording // Physica B 2008. V. 403. P. 338–341.
  40. Victora R.H., Shen X. Composite media for perpendicular magnetic recording // IEEE Trans. Magn. 2005. V. 41. P. 537–542.
  41. Wang J.P., Shen W.K., Bai J.M. Exchange coupled composite media for perpendicular magnetic recording // IEEE Trans. Magn. 2005. V. 41. P. 3181–3183.
  42. Wang J.P., Shen W.K., Hong S.Y. Fabrication and characterization of exchange coupled composite media // IEEE Trans. Magn. 2007. V. 43. P. 682–686.
  43. Schuermann K.C., Dutson J.D., Wu S.Z., Harkness S.D., Valcu B., Richter H.J., Chantrell R.W., O’Grady K. Exchange-coupling effects in perpendicular composite materials // J. Appl. Phys. 2006. V. 99. P. 08Q904-1-3.
  44. Hauet T., Dobisz E., Florez S., Park J., Lengsfield B., Terris B.D., Hellwig O. Role of reversal incoherency in reducing switching field and  switching field distribution of exchange coupled composite bit patterned media // Appl. Phys. Lett. 2009. V. 95. P. 262504-1-3.
  45. Choe G., Ikeda Y., Zhang K., Tang K., Mirzamaani M. Control of exchange coupling between granular oxide and highly exchange coupled cup layers and the effect on perpendicular magnetic switching and recording characteristics // IEEE Trans. Magn. 2009. V. 45. P. 2694–2700.
  46. Tang K., Bian X., Choe G., Takano K., Mirzamaani M., Wang G., Zhang J., Xiao Q. F., Ikeda Y., Risner-Jamtgaard J., Xu X. Design consideration and practical solution of high-performance perpendicular magnetic recording media // IEEE Trans. Magn. 2009. V. 45. P. 786–792.
  47. Makarov D., Lee J.. Brombasher C., Schubert C., Fuger M., Suess D., Filder J., Albrecht M. Perpendicular FePt based exchange coupled composite media // Appl. Phys. Lett. 2010. V. 96. P. 062501-1-4.
  48. Suess D. Exchange-coupled perpendicular media // J. Magn. Magn. Mater. 2009. V. 321. P. 545–548.
  49. Guo H.H., Liao J.L., Ma B., Zhang Z.Z., Jin Q.Y. Microstructure and magnetization reversal of L10-FePt/[Co/Pt]N exchange coupled composite films // Appl. Phys. Lett. 2012. V. 100. P. 142406-1-4.
  50. Ma B., Wang H., Zao H., San C., Acharia R., Wang J.P. Structural and magnetic properties of a core-shell type L10-FePt/Fe exchange coupled nanocomposite with tilted easy axis // J. Appl. Phys. 2011. V. 109. P. 083907-1-5.
  51. Goll D., Breitling A., Gu L., van Aken P.A., Sigle W. Experimental realization of graded L10-FePt/Fe composite media with perpendicular magnetization // J. Appl. Phys. 2008. V. 104. P. 083903-1-3.
  52. Alexandrakis V., Speliotis T., Manios E., Niarchos D., Fidler J., Lee J., Varvaro G. Hard/graded exchange spring composite media based on FePt // J. Appl. Phys. 2011. V. 109. P. 07B729-1-4.
  53. Goll D., Breitling A. Coercivity of ledge-type L10-FePt/Fe nanocomposites with perpendicular magnetization // Appl. Phys. Lett. 2009. V. 94. P. 052502-1-3.
  54. Goll D., Breitling A., Macke S. Magnetic properties of exchange-coupled L10-FePt/Fe composite elements // IEEE Trans. Magn. 2008. V. 44. P. 3472–3475.
  55. Pandey K.K.M., Chen J.S., Chow G.M., Hu J.F. L1 0 CoPt–Ta0O5 exchange coupled multilayer media for magnetic recording // Appl. Phys. Lett. 2009. V. 94. P. 232502-1-3.
  56. Jiang C.J., Chen J.S., Hu J.F., Chow G.M. FePt–TiO2 exchange coupled composite media with well-isolated columnar microstructure for high density magnetic recording // J. Appl. Phys. 2010. V. 107. P. 123915-1-4.
  57. Wang F., Zhang J., Zhang J., Wang C.L., Wang Z.F., Zeng H., Zhang M. Graded/soft/graded exchange-coupled thin films fabricated by [FePt/C]5 /Fe/[C/FePt]5 multilayer deposition and post-annealing // Appl. Surf. Sci. 2013. V. 271. P. 390–393.
  58. Wang F., Zhang J., Zhang J., Xu X.H. FePt:C/Fe graded and nongraded films with controllable coercivity fabricated by magnetron sputtering and post-annealing // J. Appl. Phys. 2011. V. 109. P. 07B731-1-3.
  59. Xu X.H., Jin T., Li X.L.,Wang F., Jiang F.X., Yang Z.G., Wu H.S. A high (001)-oriented [CoPt/C]n/Ag film for perpendicular recording media // Mater. Chem. Phys. 2006. V. 98. P. 447–449.
  60. Manna L., Scher E.C., Li L.S., Alivisatos A.P. Epitaxial growth and photochemical annealing of graded CdS/ZnS shells on colloidal CdSe nanorods // J. Am. Chem. Soc. 2002. V. 124. P. 7136–7145.
  61. Cai K.H., Li C., Zhang Y., Xu J.F., Lai H.K., Chen S.Y. Thermal annealing effects on a compositionally graded SiGe layer fabricated by oxidizing a strained SiGe layer // Appl. Surf. Sci. 2008. V. 254. P. 5363–5366.
  62. Gaur N., Pandey K.K.M, Maurer S.L., Piramanayagam S.N., Nunes R.W., Yang H., Bhatia C.S. Magnetic and structural properties of CoCrPt–SiO2-based graded media prepared by ion implantation // J. Appl. Phys. 2011. V. 110. P. 083917-1-4.
  63. Bona A.D., Luches P., Albertini F., Casoli F., Lupo P., Nasi L., D’Addato S., Gazzadi C., Valeri S. Anisotropy-graded magnetic media obtained by ion irradiation of L10 FePt // Acta Mater. 2013. V. 61. P. 4840–4847.
  64. Suess D., Schrefl T, Dittrich R., Hrkac G., Kirschner M. Exchange spring recording media for areal densities up to 10 Tbit/in2 // J. Magn. Magn. Mater. 2005. V. 290–291. P. 551–554.
  65. Suess D., Fidler, J., Zimanyi, G., Schrefl T., Visscher P. Thermal stability of graded exchange spring media under the influence of external fields // Appl. Phys. Lett. 2008. V. 92. P. 173111-1-4.
  66. Nolan T., Valcu B., Richter H.J. Effect of composite designs on writability and thermal stability of perpendicular recording media// IEEE Trans. Magn. 2011. V. 47. P. 63–68.
  67. Wang T., Mehta V., Ikeda Y., Do H., Takano K., Florez S., Terris B. D., Wu B., Graves C., Shu M., Rick R., Scherz A., Stöhr J., Hellwig O. Magnetic design evolution in perpendicular magnetic recording media as revealed by resonant small angle X-ray scattering // Appl. Phys. Lett. 2013. V. 103. P. 112403-1-4.
  68. Wang J., Sepehri-Amin H., Takahashi Y.K., Okamoto S., Kasai S., Kim J.Y., Schrefl T., Hono K. Magnetization reversal of FePt based exchange coupled composite media // Acta Mater. 2016. V. 111. P. 47–55.
  69. Wang F., Xing H., Xu X. Overcoming the trilemma issues of ultrahigh density perpendicular magnetic recording media by L10-Fe(Co)Pt materials // Spin. 2015. V. 5. № 1. P. 1530002-1-26.
  70. Berger A., Supper N., Ikeda Y., Lengsfield B., Moser A., Fullerton E.E. Improved media performance in optimally coupled exchange spring layer media // Appl. Phys. Lett. 2008. V. 93. P. 122502-1-3.
  71. Thiele J.-U., Maat S., Fullerton E.E. Magnetic and structural properties of FePt-FeRh exchange spring films for thermally assisted magnetic recording media // IEEE Trans. Magn. 2004. V. 40. P. 2537–2539.
  72. Thiele J.-U., Maat S., Fullerton E.E. FeRh/FePt exchange spring films for thermally assisted magnetic recording media // Appl. Phys. Lett. 2003. V. 82. P. 2859–2861.
  73. Kikitsu A., Kai T., Nagase T., Akiyama J.-I. A concept of exchange-coupled recording medium for heat-assisted magnetic recording // J. Appl. Phys. 2005. V. 97. P. 10P701-1-4.
  74. Ruigrok J.J.M., Coehom R., Cumpson S.R., Kesteren H.W. Disk recording beyond 100 Gb/in2: Hybrid recording //J. Appl. Phys. 2000. V. 87. P. 5398–5401.
  75. Nemoto H., Saga H., Sukeda H., Takahashi M. Exchange-coupled magnetic bilayer media for thermomagnetic writing and flux detection // Jpn. J. Appl. Phys. 1999. V. 38. P. 1841–1842.
  76. Tipcharoen W, Kaewrawang A., Siritaratiwat A. Design and micromagne-tic simulation of Fe/L10-FePt/Fe trilayer for exchange coupled composite bit  patterned media at ultrahigh areal density // Adv. Mater. Sci. Eng. 2015. V. 21. P. 504628-1-5.
  77. Suess D., Vogler C., Abert C., Bruckner F., Windl R., Breth L. Fundamental limits in heat-assisted magnetic recording and methods to overcome it with  exchange spring structures // J. Appl. Phys. 2015. V. 117. P. 163913-1-4.
  78. Shiroishi Y., Fukuda K., Tagawa I., Iwasaki H., Takenoiri S., Tanaka H., Mutoh H., Yoshikawa N. Future options for HDD storage // IEEE Trans. Magn. 2009. V. 45. P. 3816–3822.
  79. Wood R., Williams M., Kavcic A., Miles J. The feasibility of magnetic recording at 10 Tb/inch2 on conventional media // IEEE Trans. Magn. 2009. V. 445. P. 917–923.
  80. Evans R.F.L., Chantrell R.W., Nowak U., Lyberatos A., Richter H.-J. Thermally induced error: Density limit for magnetic data storage // Appl. Phys. Lett. 2012. V. 100. P. 102402-1-3.
  81. Richter H.J., Lyberatos A., Nowak U., Evans R.F.L., Chantrell R.W. The thermodynamic limits of magnetic recording// J. Appl. Phys. 2012. V. 111. P. 033909-1-8.
  82. Suess D., Schrefl T. Breaking the thermally induced write error in heat assisted recording by using low and high Tc materials // Appl. Phys. Lett. 2013. V. 102. P. 162405-1-4.
  83. Vahaplar K., Kalashnikova A.M.,  Kimel A.V., Hinzke D., Nowak U., Chantrell R.W, Tsukamoto A., Itoh A., Kirilyuk A., Rasing Th. Ultrafast path for optical magnetization reversal via a strongly nonequilibrium state // Phys. Rev. Lett. 2009. V. 103. P. 117201-1-4.
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