Thermal effect limits in ultrahigh-density magnetic recording

IEEE Transactions on Magnetics

Volumn 35, Issue 6, 1999, Pages 4423-4439

  Weller, Dieter ^a   Moser, Andreas ^a  

^a IBM ALMADEN RESEARCH CENTER   (United States)

Author keywords

Arrhenius n el model; Dynamic coercivity; High ku alloys; Magnetic recording; Signal decay; Thermal switching

Indexed keywords

ANISOTROPY; COERCIVE FORCE; MAGNETIC FIELDS; MAGNETIZATION; MATHEMATICAL MODELS; SIGNAL PROCESSING; STATISTICAL METHODS; THERMAL EFFECTS;

ARRHENIUS-NEEL STATISTICAL SWITCHING MODELS; THERMAL SWITCHING;

MAGNETIC RECORDING;

EID: 0033220894     PISSN: 00189464     EISSN: None     Source Type: Journal    
DOI: 10.1109/20.809134     Document Type: Article

References (157)

1. S. H. Charap, P.-L. Lu, Y. He, "Thermal stability of recorded information at high densities," IEEE Trans. Magn., vol. 33, p. 978, 1997.
2. E. D. Daniel, C. D. Mee, and M. H. Clark, "Magnetic recording," in The First 100 Years. New York: IEEE Press, 1998.
3. 2 recording demonstration with SV read heads and conventional narrow pole-tip write heads," IEEE Trans. Magn., vol. 35, p. 689, 1999.
4. 2 longitudinal media on a glass substrate," J. Appl. Phys., vol. 85, p. 4286, 1999.
5. R. M. White, Introduction to Magnetic Recording. New York: IEEE Press, 1984.
6. E. Grochowski and D. A. Thompson, "Outlook for maintaining areal density growth in magnetic recording," IEEE Trans. Magn., vol. 30, pp. 3797-3800, 1994.
7. E. Grochowski and R. Hoyt, "Future trends in hard disk drives," IEEE Trans. Magn., vol. 32, pp. 1850-1854, 1996.
8. D. A. Thompson, "The role of perpendicular recording in the future of hard disk storage," J. Magn. Soc. Japan, vol. 21, no. S2, p. 9, 1997.
9. J. C. Mallinson, "Scaling in magnetic recording," IEEE Trans. Magn., vol. 32, p. 599, 1996.
10. N. R. Belk, P. K. George, and G. S. Mowry, "Measurement of the intrinsic signal-to-noise ratio for high-performance rigid recording media," J. Appl. Phys., vol. 59, no. 2, p. 557, 1986.
11. T. C. Arnoldussen, "Bit cell aspect ratio: An SNR and detection perspective," IEEE Trans. Magn., vol. 34, p. 1851, 1998.
12. H. Zhou, H. N. Bertram "Scaling of hysteresis and transition parameter with grain size in longitudinal thin media," J. Appl Phys., vol. 85, p. 4984, 1999.
13. M. L. Williams and R. L. Comstock, "An analytical model of the write process in digital magnetic recording," in 17th Ann. AIP Conf. Proc., vol. 5, p. 738, 1971.
14. H. N. Bertram, Theory of Magnetic Recording. Cambridge, U.K.: Cambridge Univ. Press, 1994.
15. K. E. Johnson, "Thin film media," in Magnetic Disk Drive Technology, K. G. Ashar, Ed. New York: IEEE Press, 1997.
16. H. C. Tong, R. Ferrier, P. Chang, J. Tzeng, and K. L. Parker, "The micromagnetics of thin-film disk recording tracks," IEEE Trans. Magn., vol. 20, p. 1831, 1984.
17. T. C. Arnoldussen and H. C. Tong, "Zigzag transition profiles, noise and correlation statistics in highly oriented longitudinal film media," IEEE Trans. Magn., vol. 22, p. 889, 1986.
18. 2 areal density," IEEE Trans. Magn., vol. 26, p. 2271, 1990.
19. T. Yogi and T. A. Nguyen, "Ultrahigh density media, gigabit and beyond," IEEE Trans. Magn., vol. 29, p. 307, 1993.
20. H. Akimoto, I. Okamoto, and M. Shinohara, "Magnetic interaction in Co-Cr-Pt-Ta-Nb Media: Utilization of micromagnetic simulation," IEEE Trans. Magn., vol. 34, p. 1597, 1998.
21. M. Mirzamaani, X. Bian, M. F. Doerner, J. Li, and M. Parker, "Recording performance of thin film media with various crystallographic preferred orientations on glass substrates," IEEE Trans. Magn., vol. 34, p. 1588, 1998.
22. Y. Kubota, L. Folks, and E. E. Marinero, "Intergrain magnetic coupling and microstructure in CoPtCr, CoPtCrTa and CoPtCrB alloys," J. Appl. Phys., vol. 84, p. 6202, 1998.
23. E. C. Stoner and E. P. Wohlfarth, "A mechanism of magnetic hysteresis in heterogeneous alloys," Trans. Roy. Soc., vol. A240, p. 599, 1948.
24. M. Yu, M. F. Doerner, and D. J. Sellmyer, "Thermal stability and nanostructure of CoCrPt longitudinal recording media," IEEE Trans. Magn., vol. 34, p. 1534, 1998.
25. H. J. Richter and R. Y. Ranjan, "Relaxation effects in thin film media and their consequences," J. Magnetism Magn. Mater., vol. 193, p. 213, 1999.
26. H. N. Bertram, H. Zhou, and R. Gustafson, "Signal to noise ratio scaling and density limit estimates in longitudinal magnetic recording," IEEE Trans. Magn., vol. 34, p. 1845, 1998.
27. Spatial dependencies of Hd have been discussed in [8], [17] and e.g. Y. Zhang and H. N. Bertram, "A theoretical study of nonlinear transition shift," IEEE Trans. Magn., vol. 34, p. 1955, 1998.
28. H. Pfeiffer, "Determination of anisotropy field distribution in particle assemblies taking into account thermal fluctuations," Phys. Stat. Sol., vol. 118, p. 295, 1990.
29. R. H. Victora, "Predicted time dependence of the switching field for magnetic materials," Phys. Rev. Lett., vol. 63, p. 457, 1989.
30. L. Néel, "Théorie du trainage magnétique," Ann. Geophys., vol. 5, p. 99, 1949.
31. W. F. Brown, Jr., "Thermal fluctuations of a single-domain particle," Phys. Rev., vol. 130, p. 1677, 1963.
32. 9 Hz," private communication, to be published.
33. W. F. Brown, "Thermal fluctuations in fine ferromagnetic particles," IEEE Trans. Magn., vol. 15, p. 1196, 1979.
34. P. Gaunt, "The frequency constant for thermal activation of a ferromagnetic domain wall," J. Appl. Phys., vol. 48, p. 3470, 1977.
35. W. Wernsdorfer, E. Bonet Orozco, K. Hasselbach, A. Benoit, B. Barbara, N. Demoncy, A. Loiseau, H. Pascard, and D. Mailly, "Experimental evidence of the Néel-Brown model of magnetization reversal," Phys. Rev. Lett., vol. 78, p. 1791, 1997.
36. D. C. Crew, P. G. McCormick, and R. Street, "The interpretation of magnetic viscosity," J. Appl. D, Appl. Phys., vol. 29, p. 2313, 1996.
37. A. Moser and D. Weller, "Thermal processes and stability of longitudinal magnetic recording media," IEEE Trans. Magn., to be published.
38. S. H. Charap, "Magnetic viscosity in recording media," J. Appl. Phys., vol. 63, p. 2054, 1988.
39. C. Yang, J. M. Sivertsen, and J. H. Judy, "Time decay of the remanent magnetization in longitudinal thin film recording media as a function of distributions of grain size and easy-axis orientation," IEEE Trans. Magn., vol. 34, p. 1606, 1998.
40. Y. Zhang and H. N. Bertram, "Thermal decay in high density disk media," IEEE Trans. Magn., vol. 34, p. 3786, 1998.
41. C. P. Bean and J. D. Livingston, "Superparamagnetism," J. Appl. Phys., suppl. to vol. 30, p. 120S, 1959.
42. H. N. Bertram and H. J. Richter, "Arrhenius-Néel thermal decay in polycrystalline thin film media," J. Appl. Phys., vol. 85, p. 4991, 1999.
43. H. Kronmüller and T. Reininger, "Micromagnetic background of magnetization processes in inhomogeneous ferromagnetic alloys," J. Magnetism Magnetism Mater., vol. 112, p. 1, 1992.
44. M. P. Sharrock, "Time-dependent magnetic phenomena and particle-size effects in recording media," IEEE Trans. Magn., vol. 26, p. 193, 1990.
45. B. D. Cullity, Introduction to Magnetic Materials. Reading, MA: Addison-Wesley, 1972, p. 415.
46. M. Lederman, S. Schultz, and M. Ozaki, "Measurement of the dynamics of the magnetization reversal in individual single domain ferromagnetic particles," Phys. Rev. Lett., vol. 73, p. 1986, 1994.
47. M. Lederman, D. R. Fredkin, R. O'Barr, S. Schultz, and M. Ozaki, "Measurement of thermal switching of the magnetization of single domain particles," J. Appl. Phys., vol. 75, p. 6217, 1994.
48. D. D. Awschalom and D. P. DiVincenzo, "Complex dynamics of mesoscopic magnets," Phys. Today, vol. 48, no. 4, p. 43, 1995.
49. M. E. Schabes, "Micromagnetic theory of nonuniform magnetization processes in magnetic recording particles," J. Magnetism Magn. Mater., vol. 95, p. 249, 1991.
50. C. H. Back, D. Weller, J. Heidmann, D. Mauri, D. Guarisco, E. L. Garwin, and H. C. Siegmann, "Magnetization reversal in ultrashort magnetic field pulses," Phys. Rev. Lett., vol. 81, p. 3251, 1998.
51. J. A. Ewing, "On time-lag in the magnetization of iron," Proc. Roy. Soc., London, vol. 46, p. 269, 1889.
52. R. Street and J. C. Woolley, "A study of magnetic viscosity," Proc. Phys. Soc., vol. A62, p. 562, 1949.
53. S. Chikazumi, Physics of Magnetism. New York: Wiley, 1964, ch. 15.1.
54. R. Street and S. D. Brown, "Magnetic viscosity, fluctuation fields, and activation energies," J. Appl. Phys., vol. 76, p. 6386, 1994.
55. S. M. Stinnett, W. D. Doyle, P. J. Flanders, and C. Dawson, "High speed switching measurements in thin film disk media," IEEE Trans. Magn., vol. 34, p. 1828, 1998.
56. P. Gaunt, "Magnetic viscosity in ferromagnets I. Phenomenological theory," Philos. Magn., vol. 34, p. 775, 1976.
57. K. O'Grady, P. Dova, and H. Laidler, "Determination of critical volumes in recording media," Mat. Res. Soc. Symp., vol. 517, p. 231, 1998.
58. E. N. Abarra, I. Okamoto, and T. Suzuki, "Magnetic force microscopy analysis of thermal stability in longitudinal media," Mat. Res. Soc. Symp., vol. 517, p. 255, 1998.
59. P. Glijer, E. N. Abarra, H. Kisker, and T. Suzuki, "High resolution measurements of magnetic recordings using magnetic force mircroscopy (MFM)," IEEE Trans. Magn., vol. 32, p. 3557, 1996.
60. 2 medium," IEEE Trans. Magn., vol. 33, p. 2995, 1997.
61. E. N. Abarra, P. Glijer, H. Kisker, and T. Suzuki, "Thermal stability and micromagnetic properties of high density CoCrPtTa longitudinal media," J. Magnetism Magn. Mater., vol. 175, pp. 148-158, Nov. 1997.
62. E. Yen, H. Richter, G. Chen, and G. Rauch, "Quantitative MFM study on percolation mechanisms of longitudinal magnetic recording," IEEE Trans. Magn., vol. 33, p. 2701, 1997.
63. M. Alex, J. Scott, and T. Arnoldussen, "Quantification and spatial distribution of noise in written transitions measured with MFM," IEEE Trans. Magn., vol. 33, p. 2956, 1997.
64. A. Jander, P. Dhagat, R. S. Indeck, and M. W. Muller, "MFM observation of localized demagnetization in magnetic recordings," IEEE Trans. Magn., vol. 34, p. 1657, 1998.
65. E. N. Abarra, I. Okamoto, and T. Suzuki, "Magnetic force and Lorentz transmission electron microscopy analysis of bit transitions in longitudinal media," J. Appl. Phys., vol. 85, p. 5015, 1999.
66. D.-H. Han, J.-G. Zhu, J. H. Judy, and J. Sivertsen, "Magnetization decay in Cr/CoCtTa thin film recording media," IEEE Trans. Magn., vol. 33, p. 3025, 1997.
67. Y. Hosoe, I. Tamai, K. Tanahashi, Y. Takahashi, T. Yamamoto, T. Kanbe, and Y. Yajima, "Experimental study of thermal decay in high density magnetic recording media," IEEE Trans. Magn., vol. 33, p. 3028, 1997.
68. H. Uwazumi, J. Chen, and J. H. Judy, "Thermal decay of magnetization and readback signal of ultra-thin longitudinal CoCr12Ta2/Cr thin film media," IEEE Trans. Magn., vol. 33, p. 3031, 1997.
69. K. Rubin, J. Goldberg, H. Rosen, E. Marinero, M. Doerner, and M. Schabes, "Dynamic coercivity and thermal decay of magnetic media," Mat. Res. Soc. Symp., vol. 517, p. 261, 1998.
70. P. Dhagat, R. Indeck, and M. Muller, "Spin-stand measurement of time and temperature dependence of magnetic recordings," J. Appl. Phys., vol. 85, p. 4994, 1999.
71. N. D. Rizzo and T. J. Silva, "Thermal relaxation in the strong-demagnetizing limit," IEEE Trans. Magn., vol. 34, p. 1857, 1998.
72. M. Yu, M. F. Doerner, and D. J. Sellmyer, "Thermal stability and nanostructure of CoCrPt longitudinal recording media," IEEE Trans. Magn., vol. 34, p. 1534, 1998.
73. A. Moser, D. Weller, and M. F. Doerner, "Thermal stability of longitudinal magnetic recording media," Appl. Phys. Lett., vol. 75, no. 11, pp. 1604-1606, Sept. 1999.
74. A. Moser, D. Weller, M. E. Best, and M. F. Doerner, "Dynamic coercivity measurements in thin film recording media using a contact write/read tester," J. Appl. Phys., vol. 85, p. 5018, 1999.
75. S. M. Stinnett, J. W. Harrell, A. F. Khapikov, and W. D. Doyle, "The relationship between the dynamic coercivity and the viscosity and irreversible susceptibility in magnetic media," IEEE Trans. Magn. to be published.
76. W. D. Doyle, private communication, June 1999.
77. C. Yang, J. M. Sivertsen, T. Li, and J. H. Judy, "Experimentally determination of the distribution of relaxation time for thermally activated transition in thin film magnetic recording media," J. Appl. Phys., vol. 85, p. 5000, 1999.
78. G. R. Jonses, M. Jackson, and K. O'Grady, "Determination of grain size distributions in thin films," J. Magnetism Magn. Mater., vol. 193, p. 75, 1999.
79. M. F. Doerner, K. Tang, T. Arnoldussen, H. Zeng, M. F. Toney, and D. Weller, "Microstructure and thermal stability of advanced longitudinal media," presented at TMRC'99, San Diego, CA, Aug. 10-12, 1999.
80. J. Soderlund, L. B. Kiss, G. A. Niklasson, and C. G. Granqvist, "Lognormal size distributions in particle growth processes without coagulation," Phys. Rev. Lett., vol. 80, p. 2386, 1998.
81. A. Moser and D. Weller, "Thermal processes and stability of longitudinal magnetic recording media," IEEE Trans. Magn.. vol. 35, pp. 2808-2318, Sept. 1999.
82. P. Bruno, G. Bayreuther, P. Beauvillain, C. Chappert, G. Lugert, D. Renard, J. P. Renard, and J. Seiden, "Magnetic properties of ultrathin ferromagnetic films," J. Appl. Phys., vol. 68, p. 5759, 1990.
83. S. M. Stinnett and W. D. Doyle, "The effect of particle size on the thermal switching characteristics of metal particle tapes," IEEE Trans. Magn., vol. 34, p. 1681, 1998.
84. L. He, D. Wang, and W. D. Doyle, "Remanence coercivity of recording media in the high speed regime," IEEE Trans. Magn., vol. 31, p. 2892, 1995.
85. L. He, W. D. Doyle, L. Varga, H. Fujiwara, and P. J. Flanders, "High-speed switching in magnetic recording media," J. Magnetism Magn. Mater., vol. 155, 1996.
86. H. J. Richter, S. Z. Wu, and R. Malmhäll, "Dynamic coercivity effects in thin film media," IEEE Trans. Magn., vol. 34, pp. 1540-1542, July 1998.
87. A. Moser, M. E. Best, and D. Weller, "Calibration of write head fields by magnetic force microscopy," to be published.
88. H. N. Bertram and Q. Peng, "Numerical simulations of the effect of record field pulse length on medium coercivity at finite temperatures," IEEE Trans. Magn., vol. 34, p. 1543, 1998.
89. K.B. Klaassen, private communication, Aug. 1999.
90. K. B. Klaassen, R. G. Hirko, and J. T. Contreras, "High Speed Magnetic Recording," IEEE Trans. Magn., vol. 34, pp. 1822-1827, July 1998.
91. S. M. Stinnett, W. D. Doyle, O. Koshinka, and L. Zhang, "The relationship between high speed swiching characteristics and the fluctuation field," J. Appl. Phys., vol. 85, p. 5009, 1999.
92. N. D. Rizzo, T. J. Silva, and A. B. Kos, "Nanoseond magnetization reversal in high coercivity thin films," presented at TMRC'99, San Diego, CA, Aug. 10-12, 1999.
93. H. C. Siegmann, E. L. Garwin, C. Y. Prescott, J. Heidmann, D. Mauri, D. Weller, R. Allenspach, and W. Weber, "Magnetism with picosecond field pulses," J. Magnetism Magn. Mater., vol. 151, p. L8, 1995.
94. C. H. Back, R. Allenspach, W. Weber, S. S. P. Parkin, D. Weller, E. L. Garwin, and H. C. Siegmann, "Minimum field strength in ultrafast magnetization reversal," Science, Aug. 5, 1999.
95. G. Ju, A. V. Nurmikko, R. F. C. Farrow, R. F. Marks, M. J. Carey, and B. A. Gurney, "Ultrafast time resolved photoinduced magnetization rotation in a ferromagnetic/antiferromagnetic exchange coupled system," Phys. Rev. Lett., vol. 82, p. 3705, 1999.
96. Ch. Back and R. Allenspach, private communication, Aug. 1999.
97. N. Inaba, Y. Uesaka, A. Nakamura, M. Futamoto, Y. Sugita, and S. Narishige, "Damping constants of Co-Cr-Ta and Co-Cr-Pt thin films," IEEE Trans. Magn., vol. 33, p. 2989, 1997.
98. G. Srinivasan and A. N. Slavin, Eds, High Frequency Processes in Magnetic Materials. River Edge, NJ: World Scientific, 1994.
99. P. E. Wigen, "Microwave properties of magnetic garnet thin films," Thin Solid Films, vol. 114, pp. 135-186, 1984.
100. C. E. Patton, "Magnetic excitations in solids," Phys. Rep., vol. 103, no. 5, pp. 251-315, 1984.
101. Z. Frait and D. Fraitová", in Spin Waves and Magnetic Excitations, A. S. Borovik-Romanov and S. K. Sinha, Eds. Amsterdam, The Netherlands: North-Holland, 1988.
102. F. Schreiber, private communication, Oct. 1996.
103. R. W. Chantrell, J. D. Hannay, M. Wongsam, T. Schrefl, and H.-J. Richter, "Computational approaches to thermally activated fast relaxation," IEEE Trans. Magn., vol. 34, p. 1839, 1998.
104. V. L. Safonov, "Micromagnetic grain as a nonlinear oscillator," J. Magnetism Magn. Mater., vol. 195, p. 526, 1999.
105. V. L. Safonov and H. N. Bertram, "Magnetization reversal as a nonlinear multimode process," J. Appl. Phys., vol. 85, p. 5072, 1999.
106. H. Suhl, "Theory of the magnetic damping constant," IEEE Trans. Magn., vol. 34, p. 1834, 1998.
107. W. Yang and D. N. Lambeth, "A simulation of rotation magnetization processes in longitudinal thin-film media," IEEE Trans. Magn., vol. 33, p. 2965, 1997.
108. Y. Hosoe, I. Tamai, K. Tanahashi, Y. Takahashi, T. Yamamoto, T. Kanbe, and Y. Yajima, "Experimental study of thermal decay in high density magnetic recording media," IEEE Trans. Magn., vol. 33, p. 3028, 1997.
109. R. W. Chantrell, J. D. Hannay, M. Wongsam, T. Schrefl, and H.-J. Richter, "Computational approaches to thermally activated fast relaxation," IEEE Trans. Magn., vol. 34, p. 1839, 1998.
110. J. Zhu and H. N. Bertram, "Micromagnetic studies of magnetic thin films," J. Appl. Phys., vol. 63, p. 3248, 1988.
111. H. Kronmüller, "Micromagnetism and magnetization processes in modern magnetic materials," in Science and Technology of Nanostructured Magnetic Materials, G. C. Hadjipanayis and G. A. Prinz, Eds. New York: Plenum, p. 657, 1991.
112. _, "Micromagnetic background of hard magnetic materials," in Supermagnets, Hard Magnetic Materials, Gary J. Long and Fernande Grandjean, Eds. Amsterdam, The Netherlands: Kluwer, 1991, p. 461.
113. J. H. Kaufman, T. Koehler, A. Moser, D. Weller, and B. Jones, "Anisotropy design in magnetic media: A micromagnetics study," J. Appl. Phys., vol. 83, p. 6489, 1998.
114. 2 recording," J. Appl. Phys., vol. 79, p. 4485, 1996.
115. H. N. Bertram, H. Zhou, and R. Gustafson, "Signal to noise ratio scaling and density limit estimates in longitudinal magnetic recording," IEEE Trans. Magn., vol. 34, p. 1845, 1998.
116. 2 recording density," IEEE Trans. Magn., vol. 33, p. 2893, 1997.
117. 2 density," IEEE Trans. Magn., vol. 35, pp. 2544-2546, Sept. 1999.
118. T. C. Arnoldussen, "Bit cell aspect ratio: An SNR and detection perspective," IEEE Trans. Magn., vol. 34, p. 1851, 1998.
119. R. Wood, "Detection capacity limits in magnetic media noise," IEEE Trans. Magn., vol. 34, p. 1848, 1998.
120. G. Hurley, T. Arnoldussen, R. Wood, D. Cheng, and M. Williams, "A simulation of magnetic recording on coarsely granular media," IEEE Trans. Magn., vol. 35, pp. 2253-2255, Sept. 1999.
121. M. F. Doerner, K. Tang, T. Arnoldussen, H. Zeng, M. F. Toney, and D. Weller, "Mircrostructure and thermal stability of advanced longitudinal media," presented at TMRC'99, San Diego, CA, Aug. 9-11, 1999.
122. 2," presented at TMRC'99, San Diego, CA, Aug. 9-11, 1999.
123. H. Zhou and H. N. Bertram, "Micromagnetic study of longitudinal thin film media: Effect of grain size distribution," IEEE Trans. Magn., vol. 35, pp. 2712-2714, Sept. 1999.
124. H. Katayama, S. Sawamura, Y. Ogimoto, K. Kojima, and K. Ohta, "New magnetic recording method using laser assisted read/write technologies," J. Magn. Soc. Jpn., vol. 23, no. S1, p. 233, 1999.
125. 0 ordered FePd ferromagnets," Scripta Metallurgica et Materialia, vol. 33, nos. 10-11, pp. 1793-1805, 1995.
126. 0 ordered ferromagnets: Co-Pt, Fe-Pt, Fe-Pd and Mn-Al," Scripta Metallurgica et Materialia, vol. 30, no. 6, pp. 683-688, 1994.
127. K. J. Strnat, Rare-Earth-Cobalt Permanent Magnets, in Ferromagnetic Materials, E. P. Wohlfarth and K. H. J. Buschow, Eds. Amsterdam, The Netherlands: Elsevier, 1988, vol. 4.
128. K. H. J. Buschow, "Permanent magnet materials," in Materials Science and Technology, W. Cahn, P. Haasen, and E. J. Kramer, Eds., vol. 3B, pt. 2, pp. 451-528, 1994.
129. K. H. J. Buschow, "New developments in hard magnetic materials," Rep. Prog. Phys., vol. 54, p. 1123, 1991.
130. D. N. Lambeth, "Hard disk media: Future problems and possible solutions," presented at the 5th International Symposium Sputtering Plasma Processes ISSP'99, Kanazawa, Ishikawa, Japan.
131. Y. Liu, D. J. Sellmyer, B. W. Robertson, S. S. Shanand, and S. H. Liou, "High resolution electron microscopy and nano probe study of CoSm/Cr films, IEEE Trans. Magn., vol. 31, pp. 2740-2742, Nov. 1995.
132. D. N. Lambeth, D. E. Laughlin, S. Charap, L.-L. Lee, P. Harllee, and L. Tang, "Present status and future magnetic data storage" in, Magnetic Hysteresis in Novel Magnetic Materials, G. C. Hadjipanayis, Ed. London, U.K.: Kluwer, 1997, p. 767.
133. Y. Kubota, E. E. Marinero, and M. F. Toney, "Coercivity and magnetic anisotropy in amorphous CoSm thin films," to be published, preprint.
134. E. M. T. Velu and D. N. Lambeth, "CoSm-based high coercivity thin films for longitudinal recording," J. Appl. Phys., vol. 69, p. 5175, 1991.
135. Y. Ide, T. Goto, K. Kikuchi, K. Watanabe, J. Onagawa, H. Yoshida, and J. M. Cadogan, "Ultrahigh coercive force in epitaxial FePt(001) films," J. Magnetism Magn. Mater., pp. 177-181, vol. 245, 1998.
136. 0 thin films for longitudinal recording," IEEE Trans. Magn., vol. 31, p. 2737, 1995.
137. N. Li and B. M. Lairson, "Magnetic recording on FePt and FePtB intermetallic compound media," IEEE Trans. Magn., vol. 35, p. 1077, 1999.
138. 2 matrix," IEEE Trans. Magn., vol. 34, p. 1603, 1998.
139. K. Kikitsu, K. Yusu, K. Ichihara, and T. Tanaka "Small-dHc/dT characteristics of CoPt granular and thin film recording media," IEEE Trans. Magn., vol. 34, p. 1600, 1998.
140. B. M. Lairson, M. R. Visokay, R. Sinclair, and B. M. Clemens, "Epitaxial PtFe(001) thin films on MgO(001) with perpendicular magnetic anisotropy," Appl. Phys. Lett., vol. 62, p. 639, 1993.
141. A. Cebollada, D. Weller, J. Sticht, G. R. Harp, R. F. C. Farrow, R. F. Marks, R. Savoy, and J. C. Scott, "Enhanced magneto optical Kerr effect in spontaneously ordered FePt alloys: Quantitative agreement between theory and experiment," Phys. Rev. B, vol. 50, p. 3419, 1994.
142. S. Stavroyiannis, I. Panagiotopoulos, N. Niarchos, J. A. Christodoulides, Y. Zhang, and G. C. Hadjipanayis, "CoPt/Ag nanocomposites for high density recording media," Appl. Phys. Lett., vol. 73, p. 3453, 1998.
143. S. Stavroyiannis, I. Panagiotopoulos, D. Niarchos, J. A. Christodoulides, Y. Zhang, and G. C. Hadjipanayis, "New CoPt/Ag films for high density recording media," J. Appl. Phys., vol. 85, p. 4304, 1999.
144. I. Panagiotopoulos, S. Stavroyiannis, D. Niarchos, J. A. Christodoulides, and G. C. Hadjipanayis, "Granular CoPt/C films for high density recording media," to be published, preprint 3/99.
145. M. Yu, Y. Liu, A. Moser, D. Weller, and D. J. Sellmyer, "Nanocomposite CoPt:C films for extremely high-density recording," Appl. Phys. Lett., to be published.
146. S. Sun and C. Murray, "Synthesis of monodisperse cobalt nanocrystals and their assembly into magnetic superlattices," J. Appl. Phys., vol. 85, p. 4325, 1999.
147. Y. Yamada, T. Suzuki, H. Kanazawa, and J.C. Österman, "The origin of the large perpendicular magnetic anisotropy in CosPt alloy thin films," J. Appl. Phys., vol. 85, p. 5094, 1999 and refs. therein.
148. 2 and up for magnetic recording," IEEE Trans. Magn., vol. 33, p. 990, 1997.
149. P. R. Krauss and S. Y. Chou, "Fabrication of planar quantum magnetic disk structure using electron beam lithography, reactive ion etching, and chemical mechanical polishing," J. Vac. Sci. Technol., vol. B13, p. 2850, 1995.
150. R. M. H. New, R. F. W. Pease, and R. L. White, "Physical and magnetic properties of submicron lithographically patterned magnetic islands," J. Vac. Sci. Technol., vol. B13, p. 1089, 1995.
151. R. O'Barr, S. Y. Yamamoto, S. Schultz, X. Weihua, and A. Scherer, "Fabrication and characterization of nanoscale arrays of nickel columns," J. Appl. Phys., vol. 81, p. 4730, 1997.
152. S. Y. Chou, "Patterned magnetic nanostructures and quantized magnetic disks," Proc. IEEE, vol. 85, pp. 652-671, Apr. 1997.
153. L. Kong, L. Zhuang, and S. Y. Chou, "Writing and reading 7.5 Gbits/in/sup 2/longitudinal quantized magnetic disk using magnetic force microscope tips," IEEE Trans. Magn., vol. 33, pp. 3019-3021, Sept. 1997.
154. A. Fernandez, P. J. Bedrossian, S. L. Baker, S. P. Vernon, and D. R. Kania, "Magnetic force microscopy of single domain cobalt dots patterned using interference lithography," IEEE Trans. Magn., vol. 32, p. 4472, 1996.
155. M. Farhoud, M. Hwang, H. I. Smith, M. L. Schattenburg, J. M. Bae, K. Youcef-Toumi, and C. A. Ross, "Fabrication of large area nanostructured magnets by interferometric lithography," IEEE Trans. Magn., vol. 34, p. 1087, 1998.
156. B. D. Terris, L. Folks, D. Weller, J. E. E. Baglin, A. J. Kellock, H. Rothuizen, and P. Vettiger, "Ion beam patterning of magnetic films using stencil masks," Appl. Phys. Lett., vol. 75, no. 2, pp. 403-405, July 1999.
157. C. Chappert, H. Bernas, J. Ferré, V. Kottler, J.-P. Jamet, Y. Chen, E. Cambril, T. Devolder, F. Rousseaux, V. Mathet, and H. Launois, "Planar patterned magnetic media obtained by ion irradiation," Science, vol. 280, p. 1919, 1998.