CMRR Sub Header

H. Neal Bertram


Research Professor (CMRR), & Professor Emeritus (ECE)


Phone: 858-534-6588
Fax: 858-534-2720
nbertram@ucsd.edu
Office:CMRR Room 307

University of California, San Diego
Center for Magnetic Recording Research
9500 Gilman Drive, Mail Code 0401
La Jolla, CA. 92093-0401

Research

Recording Physics and Micromagnetics - H. Neal Bertram Professor Bertram's personal research involves analytic formulations of magnetic phenomena and recording system analysis. He is involved with reversal mechanisms in multilayer granular media focusing on reversal fields and thermal energy barriers. A long time continuing activity is the understanding of noise mechanisms in magnetic recording media. He is also engaged in analyzing the recording process in multilayer media focusing on the effective transition parameter and cross track correlation effects. Non-linear write transducer phenomena is also an interest. In addition, he performs system analysis by developing analytic formulations of error rate including all (stationary and non-stationary) noise mechanisms.

At CMRR Professor Bertram works with a variety of research groups on advanced recording projects. With Professor V. Lomakin he is engaged in numerical micromagnetic analysis of the dynamics of the recording process. With Professors Siegel and Wolf he contributes to system error rate analysis in advanced recording materials, such as patterned media. With Dr. Spada he is involved with experimental measurements of candidate recording media utilizing a "contact recording system".

In 1986 Dr. Bertram was an IEEE Distinguished Lecturer, and in 1987 he was named an IEEE Fellow. He has published a book entitled Theory of Magnetic Recording (Cambridge University Press, March 1994) and to date, has authored/co-authored over 260 scientific papers. In 1999 he received the annual technical achievement award from INSIC (International Storage Industry Consortium).

Dr. Bertram won the 2003 IEEE Reynold B. Johnson Information Storage Award. The prize is awarded each year for outstanding achievement in the field of information storage, mainly computer storage. Dr. Bertram was cited for "fundamental and pioneering contributions to magnetic recording physics research." In May 2006 Dr. Bertram received the IEEE Magnetics Society 2006 Achievement Award for "contributions to the understanding of magnetic recording".

Biography

Dr. Bertram was born in Los Angeles on June 28, 1941. He received his B.A. from Reed College in Portland, OR in 1963 and his Ph.D. in Physics from Harvard University in Cambridge, MA in 1968.

From 1968 to 1985 he was employed as a member of the research department by the Ampex Corporation in Redwood City, CA. At first Dr. Bertram focused his research on magnetization reversal and general properties of particulate magnetic media. He developed models of the AC-biased recording process, generalized reciprocity, and saturation in write-transducers. He engaged in a variety of experimental studies of magnetic tape recording, focusing on high density signals and noise. Later he became involved in experimental studies of thin film disc media and the design of high frequency write pole tips.

In 1985 he joined the University of California at San Diego as an Endowed Chair Professor in the Electrical and Computer Engineering Department associated with the (then) newly created Center for Magnetic Recording Research. At UCSD, Professor Bertram directed a research program in the physics of magnetic recording, including studies of polycrystalline thin film media, write and read transducers, fine particle tape systems and general analyses of ultimate limits in ultra high density recording. Specific studies involved: high speed dynamic magnetization reversal, effects of thermal excitation and fundamentals of dynamic relaxation. In these areas, his Ph.D. students engaged in both experimental and theoretical studies of basic issues in high density magnetic recording, including noise phenomena, nonlinearities, dynamic processes, thermally induced relaxation and large scale numerical simulations of high density magnetic recording. Dr. Bertram created graduate courses in magnetic recording theory, analysis of recording materials and magnetic recording measurements.

In 1986 Dr. Bertram was an IEEE Distinguished Lecturer, and in 1987 he was named an IEEE Fellow. He has published a book entitled Theory of Magnetic Recording (Cambridge University Press, March 1994) and to date, has authored/co-authored over 260 scientific papers. In 1999 he received the annual technical achievement award from INSIC (International Storage Industry Consortium).

Dr. Bertram won the 2003 IEEE Reynold B. Johnson Information Storage Award. The prize is awarded each year for outstanding achievement in the field of information storage, mainly computer storage. Dr. Bertram was cited for "fundamental and pioneering contributions to magnetic recording physics research." In May 2006 Dr. Bertram received the IEEE Magnetics Society 2006 Achievement Award for "contributions to the understanding of magnetic recording".

In November 2004, Dr. Bertram retired from his formal teaching and the chaired position he held for 20 years. Currently he devotes 25% of his time to CMRR projects working with students and professors. Fields of study include analytic modeling of bit error rate in high density systems, dynamic reversal processes in advanced media, analytic micromagnetic analysis of composite media and "in contact" magnetic recording measurements. He is also a part time consultant at Hitachi research labs in San Jose, CA.

Dr. Bertram and his wife Ann have a son, Seth. Dr. Bertram has had a life-long interest in music. He plays the cello, participates in numerous musical groups and gives concerts on occasion.

Projects

  • Energy barriers and thermal effects in multilayer and patterned media
  • Numerical micromagnetics in multilayer and patterned media
  • Record process modeling in multilayer and patterned media
  • Error rate analysis in recording systems
  • Rise time phenomena in high data rate recording heads
  • GMR noise analysis
  • Analysis of experimental studies of recording phenomena on both spin stand and quasi stationary contact testers.

Publications

1967-1980 

1981-1990

1991-1995

1996-2000

2001-2004 

2005-

Pending

       

        1967-1980

  1. "Magnetoelastic Interaction in EulG", H. N. Bertram and R. V. Jones, J. Appl. Phys., 38, p. 1224-1225, (1967).
  2. "Theoretical Coercivity Field for an Interacting Anisotropic Dipole Pair of Arbitrary Bond Angle", H. N. Bertram and J. C. Mallinson, J. Appl. Phys., 40, p. 1301-1302, (1969).
  3. "Switching Dynamics for an Interacting Anisotropic Dipole Pair of Arbitrary Bond Angle", H. N. Bertram and J. C. Mallinson, J. Appl. Phys., 41, p. 1102-1104, (1970).
  4. "Monte Carlo Calculation of Magnetic Anhysteresis", H. N. Bertram, J. de Physique, 32, p. 684-685, (1971).
  5. "A Theory of Contract Printing", J. C. Mallinson, H. N. Bertram and C. W. Steele, IEEE Trans. Magn., 7, p. 524-527, (1971).
  6. "Imaging Effects in Anisotropic Contact Duplication", H. N. Bertram, AIP Conf. Proc., 10, p. 1440-1444, (1972).

    1973
  7. "Anisotropy of Well Oriented g-Fe2O3 Magnetic Tape", H. Neal Bertram, AIP Conf. Proc. 18, p. 1113-1117, (1973).
  8. "Write Processes in High Density Recording", J. C. Mallinson and H. N. Bertram, IEEE Trans. Magn., 9(3), p. 329-331, (1973).
  9. "The Effect of Interactions on the Saturation Remanence of Particulate Assemblies", H. N. Bertram and A. K. Bhatia, IEEE Trans. Magn., 9(2), p. 127-133, (1973).
  10. "Long Wavelength AC Bias Recording Theory", H. N. Bertram. IEEE Trans. Magn., 10(4), p. 1039-1048, (1974).
  11. "On the Convergence of Iterative Solutions of the Integral Magnetic Field Equation", H. N. Bertram, IEEE Trans. Magn., 11(3), p. 928-933, (1975).
  12. "Wavelength Response in AC Biased Recording", H. N. Bertram, IEEE Trans. Magn., 11(5), p. 1176-1178, (1975).
  13. "A Theory of Eddy Current Limited Heads", H. N. Bertram and J. C. Mallinson, IEEE Trans. Magn., 12(6), p. 713-715, (1976).
  14. "Pole Tip Saturation in Magnetic Recording Heads", H. N. Bertram and C. W. Steele, IEEE Trans. Magn., 12(6), p. 702-706, (1976).

    1978
  15. "Anisotropic Reversible Permeability Effects in the Magnetic Reproduce Process", H. N. Bertram, IEEE Trans. Magn., 14(3), p. 111-118, (1978).
  16. "A Generalized Formula for Induced Magnetic Flux in a Playback Head", T. Wessel-Berg and H. N. Bertram, IEEE Trans. Magn., 14(3), p. 129-131, (1978).
  17. "The Effect of Pole-Tip Saturation on the Performance of a Recording Head", R. F. M. Thornley and H. N. Bertram, IEEE Trans. Magn., 14(5), p. 430-432, (1978).
  18. "The Effect of Demagnetization Fields on Recording Spectra", H. N. Bertram and R. Neidermeyer, IEEE Trans. Magn., 14(5), p. 743-745, (1978).
  19. "Recording Media Archival Attributes (Magnetic)", H. N. Bertram and A. Eshel, Report F30602-78-C-0181, United States Air Force, AFSC Rome Air Development Center, (1979).
  20. "The Print-Through Phenomenon and its Practical Consequences", H. N. Bertram, M. K. Stafford and D. R. Mills, J. of the Audio Engineering Society, 28(19), (1980).

    1981-1990                                                Back to Top

  21. "Dependence of Reproducing Gap Null on Medium Permeability and Spacing", H. N. Bertram and D. L. Lindholm, IEEE Trans. Magn., 18(3), p. 893-897, (1982).
  22. "Kinetics of the Humid Aging of Magnetic Recording Tape", H. N. Bertram and E. F. Cuddihy, IEEE Trans. Magn., 18(5), p. 993-999, (1982).
  23. "The Effect of Spacing on Demagnetization in Magnetic Recording", H. N. Bertram and R. Niedermeyer, IEEE Trans. Magn., 18(6), p. 1206-1208, (1982).
  24. "Amplitude and Bit Shift Spectra Comparisons in Thin Metallic Media", H. N. Bertram and L. D. Fielder, IEEE Trans. Magn., 29(5), p. 1606-1607, (1983).

    1984
  25. "Monte Carlo Simulation of Particulate Noise in Magnetic Recording", R. A. Arratia and H. N. Bertram, IEEE Trans. Magn., 20 (2), p. 412-420, (1984).
  26. "A Theoretical and Experimental Comparison of the Longitudinal and Vertical Modes of Magnetic Recording", J. C. Mallinson and H. N. Bertram, IEEE Trans. Magn., 20(3), p. 461-467, (1984).
  27. "Geometric Effects in the Magnetic Recording Process", H. N. Bertram, IEEE Trans. Magn., 20 (3), p. 468-478, (1984).
  28. "On the Characteristics Pole-Keeper Head Fields", J. C. Mallinson and H. N. Bertram, IEEE Trans. Magn., 20(5), p. 721-723, (1984).
  29. "The Effect of the Angular Dependence of the Particle Nucleation Field on the Magnetic Recording Process", H. N. Bertram, IEEE Trans. Magn., 20(6), p. 2094-2104, (1984).
  30. "On the Magnetization Reversal Process in CoCr Recording Media", H. N. Bertram and S. Shtrikman, J. of Magn. and Magn. Mater., 45, p. 88-90, (1984).
  31. "Interpretation of Spectral Response in Perpendicular Recording", H. N. Bertram, IEEE Trans. Magn., 21(5), p. 1395-1397, (1985).

    1986
  32. "The Magnetic Limits of Magnetic Recording", H. N. Bertram, Proc. of SMART Conference (May), San Jose, CA, (1986).
  33. "Fundamentals of the Magnetic Recording Process", H. N. Bertram, Proc. IEEE, 74(11), p. 1494-1512, (1986).
  34. "DC Modulation Noise in Thin Metallic Media and its Application for Head Efficiency Measurement", H. N. Bertram, K. Hallamasek and M. Madrid, IEEE Trans. Magn., 22(4), p. 247-252, (1986).
  35. "Computer Modeling for the Write Process in Perpendicular Recording", J-G. Zhu and H. N. Bertram,. IEEE Trans. Magn., 22(5), p. 379-381, (1986).
  36. "Particle Interaction Phenomena", H. N. Bertram. IEEE Trans. Magn., 22(5), p. 460-465, (1986).

    1987
  37. "Depth Profiling of Modulation Noise", J-M. Coutellier and H. N. Bertram, IEEE Trans. Magn., 23(1), p. 195-197, (1987).
  38. "Comparison of Thin-Film and Ring Heads for Perpendicular Recording", J-G. Zhu and H. N. Bertram, IEEE Trans. Magn., 23(1), p. 177-179, (1987).
  39. "Transition Noise Model for Longitudinal Thin-Film Media", A. Barany and H. N. Bertram, IEEE Trans. Magn., 23(2), p. 1776-1787, (1987).
  40. "Effective Volume of Interacting Particles", D. Rode, H. N. Bertram and D. R. Fredkin, IEEE Trans. Magn., 23(5), p. 2224-2226, (1987).
  41. "Computer Simulation of Nonlinear Bit Shift in Perpendicular Recording", J-G. Zhu and H. N. Bertram, IEEE Trans. Magn., 23(5), p. 2862-2864, (1987).
  42. "A Simple Iterative Model of Perpendicular Recording", C. M. Perlov and H. N. Bertram, IEEE Trans. Magn., 23(5), p. 2859-2861, (1987).
  43. "Transition Position and Amplitude Fluctuation Noise Model for Longitudinal Thin-Film Media", A. Barany and H. N. Bertram, IEEE Trans. Magn., 23(5), p. 2374-2376, (1987).
  44. "Imaging Effects in Contact Recording on Particulate Media", I. A. Beardsley and H. N. Bertram, IEEE Trans. Magn., 23(6), p. 3922-3926, (1987).

    1988
  45. "Micromagnetic Studies of Thin Metallic Films", J-G. Zhu and H. N. Bertram, J. Appl. Phys., 63(8), 3248-3253, (1988). (INVITED)
  46. "Ferromagnetic Switching in Elongated g-Fe2O3 Particles", M. E. Schabes and H. N. Bertram, J. Appl. Phys., 64, p. 5832-5834, (1988).
  47. "Recording and Transition Noise Simulations in Thin-Film Media", J-G. Zhu and H. N. Bertram, IEEE Trans. Magn., 24(6), p. 2706-2708, (1988).
  48. "Magnetization Processes in Ferromagnetic Cubes", M. E. Schabes and H. N. Bertram, J. Appl. Phys., 64, p. 1349-1359, (1988).
  49. "The Recording Process in Longitudinal Particulate Media", H. N. Bertram and I. A. Beardsley, IEEE Trans. Magn., 246), p. 3234-3248, (1988).

    1989
  50. "Transition Noise Study in Oriented Longitudinal Thin-Films", J-G. Zhu and H. N. Bertram, Presented at International Magnetics Conference, Washington, D.C., March 28-31, (1989).
  51. "Transition Noise Study in Oriented Longitudinal Thin-Films", J-G. Zhu and H. N. Bertram, Digest, INTERMAG 1989, p. BA-9, (March).
  52. "DC Modulation Noise and Demagnetizing Fields in Thin Metallic Media", G. Tarnopolsky, L. Tran, A. Barany, N. Bertram and D. Bloomquist, IEEE Trans. Magn., 25(4), p. 3160-3165, (1989).
  53. "Effects of Applied Field Inhomogeneities on the Magnetization Reversal of Elongated g-Fe2O3 Particles", M. E. Schabes and H. N. Bertram, Digest, INTERMAG 1989, p. EP-11, (March), IEEE Trans. Magn., 25(5), p. 3662-3664, (1989).
  54. "Magnetization Reversal in CoCr Perpendicular Thin-Films", J-G. Zhu and H. N. Bertram, J. Appl. Phys. 66(3), p. 1291-1307, (1989).
  55. "Characterization of Head Saturation", D. Rode and H. N. Bertram, IEEE Trans. Magn., 25(1), p. 703-709, (1989).

    1990
  56. "Magnetization Reversal of Cobalt Modified g-Fe2O3 Particles", M. E. Schabes and H. N. Bertram, J. Appl. Phys., 67(9), p. 5149-5151, (1990).
  57. "Magnetization Fluctuations in Uniformly Magnetized Thin-Film Recording Media", T. J. Silva and H. N. Bertram, IEEE Trans. Magn., 26(6), p. 3129-3139, (1990).
  58. "Study of Noise Sources in Thin-Film Media", J-G. Zhu and H. N. Bertram, Digest, INTERMAG 1990, p. EB-07, (April), IEEE Trans. Magn., 26(5), p. 2140-2142, (1990)..

    1991-1995                                              Back to Top

  59. "Self-Organized Behavior in Thin-Film Recording Media", J-G. Zhu and H. N. Bertram, J. Appl. Phys., 69(8), p. 4709-4711, (1991).
  60. "Reversal Mechanisms and Domain Structures in Thin-Film Recording Media", J-G. Zhu and H. N. Bertram, J. Appl. Phys., 69(8), p. 6084-6089, (1991). (INVITED)
  61. "Domain-Wall Dynamic Instability", S. W. Yuan and H. N. Bertram, J. Appl. Phys., 69(8), p. 5874-5876, (1991).
  62. "Magnetization Fluctuations and Characteristic Lengths for Sputtered CoP/Cr Thin-Film Media", G. J. Tarnopolsky, H. N. Bertram, and L. T. Tran, J. Appl. Phys., 69(9), p. 4730-4732, (1991).
  63. "Domain Wall Structures and Dynamics in Thin-Films", S. W. Yuan and H. N. Bertram, IEEE Trans. Magn., 27(6), p. 5511-5513, (1991).
  64. "Domain-Wall Dynamic Transitions in Thin-Films", S. W. Yuan and H. N. Bertram, Phys. Rev. B-Condensed Matter, 44(22), p. 12395-12405, (1991).
  65. "Statistical Data Analysis of Magnetic Recording Noise Mechanisms", S. W. Yuan and H. N. Bertram, IEEE Trans. Magn., 28(1), p. 84-92, (1992).
  66. "A Simple Statistical Model of Partial Erasure in Thin-Film Disk Magnetic Recording Systems", R. D. Barndt, A. J. Armstrong, H. N. Bertram, and J. K. Wolf, IEEE Trans. Magn., 27(6), p. 4978-4980, (1991).
  67. "Simulations of Torque Measurements and Noise in Thin-Film Magnetic Recording Media", H. Neal Bertram and J-G Zhu, IEEE Trans. Magn., 27(6), p. 5043-5045, (1991).
  68. "Magnetization Structures in Thin-Film Recording Media", J-G. Zhu and H. N. Bertram, IEEE Trans. Magn., 27(5), p. 3553-3562, (1991).
  69. "Modeling the Effect of Head Saturation in High Density Tape Recording", D. Wachenschwanz and H. N. Bertram, IEEE Trans. Magn., 27(6), p. 4981-4983, (1991).
  70. "Nonlinear Effects in High-Density Tape Recording", A. J. Armstrong, H. N. Bertram, R. D. Barndt, and J. Wolf, IEEE Trans. Magn., 27(5), p. 4366-4376, (1991).

    1992
  71. "Fundamental Magnetization Processes in Thin Film Recording Media", H. N. Bertram and J-G. Zhu, in Solid State Physics Review, Vol. 46, p. 271-371, eds. H. Ehrenreich and D. Turnbull, Academic Press, 1992.
  72. "Magnetization Correlations and Noise in Thin Film Recording Media", H. Neal Bertram and R. Arias, J. Appl. Phys. 71(7), p. 3439-3454, (1992).
  73. "Magnetic Thin Film Domain Wall Motion Under Dynamic Fields", S. W. Yuan and H. N. Bertram, J. Appl. Phys. 72(3), p. 1033-1038, (1992).
  74. "Experimental Studies of Nonlinearities in High Density Disk Recording", H. G. Lin, R. Barndt, H. N. Bertram, and J. K. Wolf, Digest, INTERMAG 1992, p. 483, (April), IEEE Trans. Magn., 28(5), p. 3279-3281, (1992).
  75. "Phenomenology of dM Curves and the Magnetic Interactions", X. Che and H. N. Bertram, J. Magn. Magn. Mater., 116(1-2), p. 21-127, (1992).
  76. "Energy Barriers for Thermal Reversal of Interacting Single Domain Particles", W. Chen, S. Zhang and H. N. Bertram. J. Appl. Phys. 71(11), p. 5579-5584, (1992).
  77. "Size Effects of Switching Fields of Thin Permalloy Particles", S. W. Yuan, H. N. Bertram, J. F. Smyth, and S. Schultz. Digest, INTERMAG 1992, p. 432, (April). IEEE Trans. Magn., 28(5), p. 3171-3173, (1992).
  78. "Inhomogeneities and Coercivity of Soft Permalloy Thin Films", S. W. Yuan and H. Neal Bertram, Digest, INTERMAG 1992, p. 335, (April), IEEE Trans. Magn., 28(5), p. 2916-2918, (1992).
  79. "Fast Adaptive Algorithms for Micromagnetics", S. W. Yuan and H. N. Bertram, IEEE Trans. Magn., 28(5), p. 2031-2036, (1992).
  80. "Disorder and Coercivity in Magnetic Particle Systems", Y. Zhao and H. N. Bertram, J. Magn. Magn. Mater., 144(3), p. 329-335, (1992).
  81. "Improved Calibration Techniques for High Density Tape Recording System", I. A. Beardsley, A. Armstrong, and H. N. Bertram, IEEE Trans. Magn., 28(6), p. 3417-3422, (1992).
  82. "Theory of Nonlinearities and Pulse Asymmetry in High Density Tape Recording", H. N. Bertram, A. J. Armstrong, J. K. Wolf, and I. Beardsley, Digest, INTERMAG 1992, p. 248, (April), IEEE Trans. Magn., 28(5), p. 2701-2706, (1992). (INVITED)

    1993
  83. "Ultra High Density Recording for Magnetoresistive Heads", S. W. Yuan and H. N. Bertram, Digest, INTERMAG 1993, p. CA-02, (April).
  84. "Micromagnetic Modeling of a Dual Magnetoresistive Head", H. Smith, S. Yuan and H. N. Bertram, Digest, TMRC 1993, p. O-54, (Sept).
  85. "General Analysis of Noise in Recorded Transitions in Thin-Film Recording Media", H. N. Bertram and X. Che, IEEE Trans. Magn., 29(2), p. 201-208, (1993).
  86. "Dynamics of Nonlinearities in High Density Recording", X. Che and H. N. Bertram, IEEE Trans. Magn., 29(1), p. 317-323, (1993).
  87. "Magnetization Correlations in Thin Film Media in the Presence of a Recorded Transition", H. N. Bertram, I. A. Beardsley and X. Che. J. Appl. Phys., 73(3), p. 5545-5547, (1993).
  88. "Noise Analysis and Image Focusing for Magnetic Force Microscopy", X. Che, M. Lederman, G. A. Gibson, H. N. Bertram, and S. Schultz, J. Appl. Phys., 73(10), p. 5805-5807, (1993).
  89. "Domain Wall Dynamics in Thick Permalloy Films", S. W. Yuan and H. N. Bertram, J. Appl. Phys, 73(10), p. 5992-5994, (1993).
  90. "Study of Magnetic Recording Transitions at Very Low Flying Heights", X. Che and H. N. Bertram, J. Appl. Phys, 73(10), p. 6004-6006, (1993).
  91. "Micromagnetics of Small Unshielded MR Elements", S. W. Yuan and H. N. Bertram, J. Appl. Phys, 73(10), p. 6235-6237, (1993).
  92. "Fields and Transforms for Thin Film Heads", G. A. Bertero, H. N. Bertram and D. M. Barnett, IEEE Trans. Magn., 29(1), p. 67-76, (1993).
  93. "Overwrite in Thin Film Disk Recording Systems", G. H. Lin, Y. Zhao and H. N. Bertram, IEEE Trans. Magn., 29(6), p. 4215-4223, (1993).
  94. "Eddy Current Damping of Thin Film Domain Walls", S. W. Yuan and H. N. Bertram, Digest, INTERMAG 1993, p. AC-05, (April), IEEE Trans. Magn., 29(6), p. 2515-2517, (1993).
  95. "Experimental Studies of Noise Autocorrelation in Thin Film Media", G. H. Lin and H. N. Bertram, Digest, INTERMAG 1993, p. FB-01, (April), IEEE Trans. Magn., 29(6), p. 3697-3699, (1993).
  96. "Nonlinearities and Noise in Perpendicular Dibit Recording", X. Che and H. N. Bertram, IEEE Trans. Magn., 29(6), p. 3739-3741, (1993).
  97. "Magnetoresistive Heads for Ultra High Density Recording", S. W. Yuan and H. N. Bertram, IEEE Trans. Magn., 29(6), p. 3811-3816, (1993). (INVITED)
  98. "Biasing Characteristics of Unshielded, Boundary Exchange-Coupled SAL/MR Sensors", S. H. Laio, S. W. Yuan and H. N. Bertram, Digest, INTERMAG 1993, p. GP-06, (April), IEEE Trans. Magn., 29(6), p. 3873-3875, (1993).
  99. "Studies of Nonlinear Bit Shift and Partial Erasure Using Pseudo-Random Sequence", X. Che, H. N. Bertram, and M. K. Bhjattacharyya, Digest, INTERMAG 1993, p. EC-01, (April), IEEE Trans. Magn., 29(6), p. 3972-3974, (1993).
  100. "PRML Performance Estimation Considering Medium Noise Down Track Correlations", X. Che, L. C. Barbosa, and H. N. Bertram, Digest, INTERMAG 1993, p. GQ-13, (April), IEEE Trans. Magn., 29(6), p. 4062-4064, (1993).

    1994
  101. "Theory of Magnetic Recording", H. Neal Bertram, Cambridge University Press, England, 1994.
  102. "The Physics of Magnetic Recording", H. Neal Bertram, in Applied Magnetism, p. 1-38, eds. R. Gerber, C. D. Wright and G. Asti, Kluwer Academic Publishers, 1994.
  103. "Cross-track Characteristics of Shielded MR Heads", S. W. Yuan, H. N. Bertram and M. Bhattacharyya, IEEE Trans. Magn., 30(2), p. 381-387, (1994). (INVITED)
  104. "Off-Track Spacing Loss of Shielded MR Heads", S. W. Yuan and H. N. Bertram, IEEE Trans. Magn., 30(3), p. 1267-1273, (1994).
  105. "A Simplified Model of High Density Tape Recording", D. Wei, H. N. Bertram, and F. Jeffers, IEEE Trans. Magn., 30(5), p. 2739-2749, (1994).
  106. "Transition Noise Analysis of Thin Film Magnetic Recording Media", B. Slutsky and H. N. Bertram, IEEE Trans. Magn., 30(5), p. 2808-2817, (1994).
  107. "Transition Noise Spectral Measurements in Thin Film Media", G. H. Lin and H. N. Bertram, IEEE Trans. Magn., 30(6), p. 3987-3989, (1994).
  108. "The Relationship of Medium Noise to System Error Rate in a PRML Channel", J. Fitzpatrick, H. N. Bertram, X. Che, L. C. Barbosa and G. H. Lin, IEEE Trans. Magn., 30(6), p. 3990-3995, (1994). (INVITED)
  109. "Nonuniform Switching of Single Domain Particles at Finite Temperatures", H-B. Braun and H. N. Bertram, J. Appl. Phys., 75(9), p. 4609-4616, (1994).
  110. "Noise Correlations in Dibit Recording", H. G. Lin, H. N. Bertram and R. Simmons, J. Appl. Phys., 75(10), p. 5765-5767, (1994).
  111. "Micromagnetics of GMR Spin-Valve Heads", S. W. Yuan and H. N. Bertram, J. Appl. Phys., 75(10), p. 6385-6387, (1994).
  112. "Micromagnetic Studies of Medium Noise Mechanisms", X. Che and H. N. Bertram, J. Appl. Phys., 75(10), p. 6779-6781, (1994).

    1995
  113. "The Effect of MR Head Geometry on Playback Pulse Shape and Spectra", E. Champion and H. N. Bertram, IEEE Trans. Magn., 31(4), p. 2461-2470, (1995).
  114. "Micromagnetic Modeling of Magnetic Anisotropy in Textured Thin-Film Media", Y. Zhao and H. N. Bertram, J. Appl.. Phys., 77(12), p. 6411-6415, (1995).
  115. "Linear Signal Analysis of Shielded AMR and Spin Valve Heads", H. N. Bertram, IEEE Trans. Magn., 31(6), p. 2573-2578, (1995). (INVITED)
  116. "Micromagnetic and Experimental Studies of CoPtCr Polycrystalline Thin Film Media with Bicrystal Microstructure", Q. Peng, H. N. Bertram, M. Doerner, S. Lambert, M. Mirzamaani, N. Fussing and D. Margulies, IEEE Trans. Magn., 31(6), p. 2821-2823, (1995).
  117. "The Effect of Interface Dispersion on Noise and Hysteresis in Permanent Magnet Stabilized MR Elements", E. Champion and H. N. Bertram, IEEE Trans. Magn., 31(6), p. 2642-2644, (1995).
  118. "Modeling and Analysis of Overwrite in Thick Particulate Media", D. Wei, A. Friedmann, H. N. Bertram and R. Dee, IEEE Trans Magn., 31(6), p. 2898-2900, (1995).


    1996-2000                                              Back to Top

  119. "Notes on the Problem of Magnetization Reversal", R. Arias, H. N. Bertram and H. Suhl, in Nonlinear Microwave Signal Processing: Towards a New Range of Devices, p. 3-11, eds., R. Marcelli and S. A. Nikitov, Kluwar Academic Publishers, 1996.
  120. "Hysteresis and Baseline Shift in Permanent Magnet Stabilized MR/SAL Heads", E. Champion and H. N. Bertram, . Digest, TMRC 1995, p. A-1, (July), IEEE Trans. Magn., 30(1), p. 13-18, (1996). (INVITED)
  121. "Evolution of Bicrystal Media Development", G-L. Chen, J. K. Chang, Q. Chen, Q. Peng, Z-H. Lin, E. Yen, G-L. Chen, H. N. Bertram and R. Sinclair, Digest, TMRC 1996, p. A-4, (August).
  122. "Scanning Magneto-Resistance Microscopy (SMRM) as a Diagnostic for High Density Recording", S. Y. Yamamoto, S. Schultz, and H. N. Bertram, Digest, TMRC 1996, p. B-2, (August).
  123. "Texture Induced Noise and its Impact on System Performance", G. H. Lin, X. Xing, K. E. Johnson and H. N. Bertram, Digest, TMRC 1996, p. E-1, (August).
  124. "Micromagnetic Studies of Inhomogeneous CoPtCr Bicyrstal Thin Film Media", Q. Peng and H. N. Bertram, J. Appl. Phys., 79(8), p. 916-4918, (1996).
  125. "Experimental Analysis of the Effects of Tape Thickness on Magnetic Recording", A. Friedmann, D. Wei, H. N. Bertram, J. K. Wolf, R. Swanson and F. Jeffers, J. Appl. Phys. 79(8), p. 5658-5660, (1996).
  126. "Signals and Nonlinearities in Thin Metal-Particle Tape", D. Wei, H. N. Bertram and A. Friedmann, J. Appl. Phys. 79(8), p. 5661-5663, (1996).
  127. "Experimental Studies of Nonlinearities in MR Head", X. Xing and H. N. Bertram, J. Appl. Phys.79(8), p. 5883-5885, (1996).
  128. "Interlayer Coupling and Surface Roughness in GMR Spin Valve Structures", D. Wei and H. N. Bertram, IEEE Trans. Magn., 32(5), p. 3434-3436, (1996).
  129. "Pulse Distortion in MR and GMR Playback Heads", E. Champion and H. N. Bertram, IEEE Trans. Magn., 32(5), p. 3452-3454, (1996).
  130. "Micromagnetic Studies of Microstructural Dependence of Track Edge Recording on Signal and Nonlinearities in Longitudinal Thin Film Media", Q. Peng and H. N. Bertram, IEEE Trans. Magn., 32(5), p. 3566-3568, (1996).
  131. "Effect of Substrate Texture on Thin Film Disk Noise", X. Xing, G. H. Lin, K. E. Johnson and H. N. Bertram, IEEE Trans. Magn., 32(5), p. 3575-3577, (1996).
  132. "Across-The-Track Performance of Dual Stripe Magnetoresistive Heads", R. J. Davidson, R. F. Simmons, E. Champion, H. N. Bertram and S. H. Charap, IEEE Trans. Magn., 32(5), p. 3929-3931, (1996).
  133. "Measurements of Crystalline Anisotropy of Longitudinal Media", J. K. Chang, Q. Peng, H. N. Bertram and R. Sinclair, IEEE Trans. Magn., 32(5), p. 4902-494, (1996).

    1997
  134. "Tiny grains and giant magnetoresistance: Numerical micromagnetics", H. N. Bertram and C. Seberino, in Gather/Scatter, San Diego Supercomputer Center Publication, vol. 13, no. 2, p. 4-5, (1997).
  135. "Fast Thermal Reversal of Magnetic Particles", R. Arias and H. N. Bertram, J. Magn. Magn. Mater. 171, p. 209-217, (1997).
  136. "Micromagnetic Studies of Switching Speed in Longitudinal and Perpendicular Polycrystalline Thin Film Recording Media at Ultra High Densities", Q. Peng and H. N. Bertram, J. Appl. Phys., 81(8), p. 4384-4386, (1997).
  137. "Micromagnetic Simulations with Eddy Currents of Rise Time in Thin Film Write Heads", G. M. Sandler and H. N. Bertram, J. Appl. Phys, 81(8), p. 4513-4515, (1997).
  138. "PW50, D50 and Playback Voltage Formulae for Shielded MR Heads", Y. Zhang and H. N. Bertram, J. Appl. Phys, 81(8), p. 4897-4899, (1997).
  139. "Overwrite in Particulate Tape Media", D. Wei, H. N. Bertram, and R. H. Dee, IEEE Trans. Magn., 33(1), p. 836-843, (1997).
  140. "Texture Induced Noise and Its Impact on System Performance", G. H. Lin, X. Xing, K. E. Johnson and H. N. Bertram, IEEE Trans. Magn., 33(1), p. 950-955, (1997). (INVITED)
  141. "Evolution of Bicrystal Media Development", G-L. Chen, J. K. Chang, Q. Chen, Q. Peng, Z-H. Lin, E. Yen, G-L. Chen, H. N. Bertram and R. Sinclair, IEEE Trans. Magn., 33(2), p. 885-890, (1997). (INVITED)
  142. "Scanning Magneto-Resistance Microscopy (SMRM) as a Diagnostic for High Density Recording", S. Y. Yamamoto, S. Schultz, Y. Zhang and H. N. Bertram, IEEE Trans. Magn., 33(2), p. 891-896, (1997).
  143. "Playback Pulse Shape and Spectra for Shielded MR Heads", Y. Zhang, S. Shtrikman and H.N. Bertram, IEEE Trans. Magn. 33(2), p. 1093-1103, (1997).
  144. "Micromagnetic Studies of Recording Dynamics and Switching Speed in Longitudinal Thin Film Media", Q. Peng and H. N. Bertram, Digest, INTERMAG 1997, p. ET-03, (April), IEEE Trans. Magn., 33(5), p. 2677-2679, (1997).
  145. "Micromagnetic Studies of Disk Drive Servo Performance for Ultra-High Density Magnetic Recording", E. Champion, R. J. Kadlec and H. N. Bertram, Digest, INTERMAG 1997, p. ET-04, (April), IEEE Trans. Magn., 33(5), p. 2680-2682, (1997).
  146. "Dynamics of Reversal in Nonuniformly Magnetized Single Particles with Thermal Noise", E. D. Boerner and H. N. Bertram, Digest, INTERMAG 1997, p. BB-04, (April).
  147. "Micromagnetics of Needlelike Particles", C. Seberino and H. N. Bertram, Digest, INTERMAG 1997, p. BB-05, (April).
  148. "Analysis of Transition Noise in Thin Film Media", X. Xing and H. N. Bertram, Digest, INTERMAG 1997, p. AB-08, (April), IEEE Trans. Magn., 33(5), p. 2959-2961, (1997).
  149. "Dynamics of Thermally Activated Reversal in Nonuniformly Magnetized Single Particles", E. D. Boerner and H. N. Bertram, IEEE Trans. Magn., 33(5), p. 3052-3054, (1997).
  150. "Micromagnetics of Long Ferromagnetic Particles", C. Seberino and H. N. Bertram, IEEE Trans. Magn., 33(5), p. 3055-3057, (1997).
  151. "Magnetization Distribution in Thin Films with Perpendicular Surface Anisotropy", H. N. Bertram and David I. Paul, J. Appl. Phys. 82(5), p. 2439-2446, (1997).
  152. "Localized surface nucleation of magnetization reversal", H. Suhl and H. N. Bertram, J. Appl. Phys, 82(12), p. 6128-6137, (1997).

    1998
  153. "Multi Methods for Computation of Demagnetization Fields in Magnetic Recording Problems", I. A. Tsukerman, A. Plaks and H. N. Bertram, Abstract, 7th Joint MMM-INTERMAG Conference (January), p. 50, (1998).
  154. "Numerical simulations of the effect of record field pulse length on medium coercivity at finite temperatures", H. N. Bertram and Q. Peng, Abstract, 7th Joint MMM-INTERMAG Conference, p. 11, (January), IEEE Trans. Magn. 34(4), p. 1543-1545, (1998).
  155. "Non-Arrhenius behavior in single domain particles", E. D. Boerner and H.N. Bertram, Abstract, 7th Joint MMM-INTERMAG Conference, p. 201, (January), IEEE Trans. Magn. 34(4), p. 1678-1680, (1998).
  156. "Signal to noise ratio scaling and density limit estimates in longitudinal magnetic recording", H. N. Bertram, H. Zhou and R. Gustafson, IEEE Trans. Magn. 34(4), p. 1845-1847, (1998).
  157. "A theoretical study of nonlinear transition shift", Y. Zhang and H. N. Bertram, IEEE Trans. Magn. 34(4), p. 1955-1957, (1998).
  158. "Thermal decay in high density disk media", Y. Zhang and H. N. Bertram, IEEE Trans. Magn., 34(5), p. 3786-3793, (1998).
  159. "Multigrid methods for computation of magnetostatic fields in magnetic recording problems", I. Tsukerman, A. Plack and H. N. Bertram, J. Appl. Phys. 83(11), p. 6344-6346, (1998).

    1999
  160. "Numerical simulations of hysteresis in longitudinal magnetic tape", H. N. Bertram and C. Seberino, J. of Magn. and Magn. Mater 193, p. 388-394, (1999).
  161. "Scaling of hysteresis and transition parameter with grain size in longitudinal thin film media", H. Zhou and H. N. Bertram, J. Appl. Phys., 85(8), p. 4982-4984, (1999).
  162. "Arrhenius-Néel thermal decay in polycrystalline thin film media", H. N. Bertram and H. J. Richter, J. Appl. Phys., 85(8), p. 4991-4993, (1999).
  163. "Magnetization reversal as a nonlinear multimedia process", V. L. Safonov and H. N. Bertram, J. Appl. Phys., 85(8), p. 5072-5074, (1999).
  164. "Determination of the magnetic damping constant in NiFe films", G. M. Sandler, H. N. Bertram, T. J. Silva and T. M. Crawford, J. Appl. Phys., 85(8), p. 5080-5082, (1999).
  165. "Writing on perpendicular patterned media at high density and data rate", E. D. Boerner and H. N. Bertram, J. Appl. Phys., 85(8), p. 5318-5320, (1999).
  166. "Numerical study of hysteresis and morphology in elongated tape particles", C. Seberino and H. N. Bertram, J. Appl. Phys., 85(8), p. 5543-5545, (1999).
  167. "Analysis of the effect of write field rise time on signal, noise and nonlinear transition shift", X. Xing and H. N. Bertram, J. Appl. Phys., 85(8), p. 5861-5863, (1999).
  168. "Error rate analysis of PR channels in the presence of texture noise", X. Xing and H. N. Bertram, IEEE Trans. Magn. 35(3), p. 2070-2079, (1999).
  169. "Micromagnetic study of longitudinal thin film media: Effect of grain size distribution", H. Zhou, H. N. Bertram, M. Doerner and M. Mirzamaani, Digest, INTERMAG 1999, p. EB-03, (May). IEEE Trans. Magn., 35(5), p. 2712-2714, (1999).
  170. "Thermal decay of signal and noise in high density thin film media", Y. Zhang and H. N. Bertram, IEEE Trans. Magn., 35(5), p. 4326-4338, (1999).

    2000
  171. "Extending the limits of magnetic recording", H. N. Bertram, H. Zhou, C. Seberino, A. Majumdar, S. Johnson, B. Sinkovits, EnVision, 16(2), p. 14, (2000).
  172. "Dynamics of magnetization reversal", V. L. Safonov and H. N. Bertram, American Physical Society Bulletin, 45(1), p. 520, March 2000. (INVITED).
  173. "Dynamic relaxation in thin films", E. Boerner, H. N. Bertram, and H. Suhl, J. Appl. Phys., 87(9), p. 5389-5391, (2000). [PDF  ucsd only]
  174. "Intrinsic mechanisms of nonlinear damping in magnetization reversal", V. L. Safonov and H. N. Bertram, J. Appl. Phys., 87(9), p. 5508-5510, (2000). [PDF  ucsd only]
  175. "Effects of head field pulse and rise time on subnanosecond magnetization reversal in longitudinal thin film media", M. E. Schabes, H. Zhou and H. N. Bertram, J. Appl. Phys., 87(9), p. 5666-5668, (2000). [PDF  ucsd only]
  176. "Micromagnetic study of dynamic switching constant in longitudinal thin film media", A. F. Torabi, H. Zhou and H. N. Bertram, J. Appl. Phys., 87(9), p. 5669-5671, (2000). [PDF  ucsd only]
  177. "Micromagnetic analysis of anisotropy orientation in high density longitudinal magnetic recording", H. Zhou, H. N. Bertram, M. Doerner and M. Mirzamaani, J. Appl. Phys., 87(9), p. 5675-5677, (2000). [PDF  ucsd only]
  178. "‘Dynamic-thermal’ reversal in fine micromagnetic grain: time dependence of coercivity", V. L. Safonov and H. N. Bertram, J. Appl. Phys., 87(9), p. 5681-5683, (2000). [PDF  ucsd only]
  179. "SNR and density limit estimates: A comparison of longitudinal and perpendicular recording", H. N. Bertram and M. Williams, IEEE Trans. Magn., 36(1), p. 4-9, (2000). [PDF  ucsd only]
  180. "Effect of grain size distribution on recording performance in longitudinal thin film media", H. Zhou and H. N. Bertram, IEEE Trans. Magn., 36(1), p. 61-66, (2000). [PDF  ucsd only]
  181. "Analysis of tape surface roughness by magnetic recording and mechanical methods", P. Luo, S. Tan, H. N. Bertram, G. F. Hughes, F. E. Talke, IEEE Trans. Magn., 36(1), p. 189-194, (2000). [PDF  ucsd only]
  182. "Impurity relaxation mechanism for dynamic magnetization reversal in a single domain grain", V. L. Safonov and H. N. Bertram, Phys. Review B, 61(22), p. 893-896, (2000). [PDF  ucsd only]
  183. "Experimental study of the off-track dependence of medium noise using a mode projection method", Z. Jin, K. Zhang, G.-H. Lin, and H. N. Bertram, Digest, INTERMAG 2000, p. 680 (April), IEEE Trans. Magn., 36(5), p. 2145-2156, (2000). (INVITED) [PDF  ucsd only]
  184. "A growth model for polycrystalline thin film media: Comparison of bicrystal and unicrystal grain structures", Z. Jin, M. Doerner, and H. N. Bertram, Digest, INTERMAG 2000, p. 493, (April), IEEE Trans. Magn., 36(5), p. 2294-2296, (2000). [PDF  ucsd only]
  185. "Reversal field versus pulse time: Theoretical and experimental comparison", H. N. Bertram and V. L. Safonov, IEEE Trans. Magn., 36(5), p. 2447-2449, (2000). [PDF  ucsd only]
  186. "Micromagnetic recording model of pole-tip saturation effects", J. van Ek, M. Plumer, H. Zhou and H. N. Bertram, IEEE Trans. Magn., 36(6), p. 3975-3983, (2000). [PDF  ucsd only]
  187. Magnetic analysis of contact head/tape spacing", P. Luo, S. Tan, H. N. Bertram, G. Hughes and F. E. Talke, IEEE Trans. Magn., 36(6), p. 3984-3990, (2000). [PDF  ucsd only]
  188. "Simulation of the effect of medium noise on servo position error signal detection in longitudinal recording", Z. Jin and H. N. Bertram, IEEE Trans. Magn., 36(6), p. 4011-4018, (2000). [PDF  ucsd only]


    2001-2004                                           Back to Top

  189. "Magnetization dynamics and thermal fluctuations in fine grains and films", V. Safonov and H. N. Bertram, in The Physics of High Density Magnetic Recording, p. 81-109, eds. M. Plumer, J. van Ek and D. Weller, Springer-Verlag Publishers, (2001).
  190. "Spin-wave dynamic magnetization reversal in a ‘quasi’ single domain magnetic grain", V. L. Safonov and H. N. Bertram, Phys. Rev. B 63 094419(11), (2001). [PDF  ucsd only]
  191. "Modeling the effect of interactions in granular magnetic films", A. D. Liu and H. N. Bertram, J. Appl. Phys., 89(5), p. 2861-2867, (2001).[PDF  ucsd only]
  192. "The effect of uniaxial quartic anisotropy on thermal stability of magnetic nanograins", H. N. Bertram and V. L. Safonov, Applied Physics Letters, 79(26), p. 4402-4404, (2001). [PDF  ucsd only]
  193. "Concise, efficient three-dimensional fast multipole method for micromagnetics", C. Seberino and H. N. Bertram, IEEE Trans. Magn., 37(3), p. 1078-1086, (2001). [PDF  ucsd only]
  194. "Three dimensional micromagnetic analysis of write head dynamics and field patterns", K. Gao and H. N. Bertram, IEEE Trans. Magn., 37(4), p. 1373-1375, ( 2001). [PDF  ucsd only]
  195. "A model for bit error rate degradation during thermal decay", Z. Jin. H. Ide, H. Zhou, P. Luo and H. N. Bertram, IEEE Trans. Magn., 37(4), p. 1393-1395, (2001). [PDF  ucsd only]
  196. "Micromagnetic study of anisotropy sources in textured longitudinal media", G. Khanna, B. M. Clemens, H. Zhou and H. N. Bertram, IEEE Trans. Magn., 37(4), p. 1468-1470, (2001). [PDF  ucsd only]
  197. "Analytic solution for magnetic orientation between grains", D. I. Paul, C. M. Robson and H. N. Bertram, IEEE Trans. Magn., 37(4), p. 1478-1480, (2001). [PDF  ucsd only]
  198. "Dynamic-thermal effects in thin film media", H. N. Bertram, X. Wang, and V. L. Safonov. IEEE Trans. Magn., 37(4), p. 1521-1527, (2001). [PDF  ucsd only]
  199. "Collective thermal fluctuations in nominally ‘independent’ granular recording media: Application to thermal decay", V. L. Safonov and H. N. Bertram, IEEE Trans. Magn., 37(4), p. 1550-1553, (2001). [PDF  ucsd only]
  200. "Effect of intergranular exchange on thermal energy barrier distributions in longitudinal magnetic recording", H. Zhou, H. N. Bertram, A. F. Torabi and M. L. Mallary, IEEE Trans. Magn., 37(4), p. 1558-1560, ( 2001). [PDF  ucsd only]
  201. "Micromagnetic study of switching speed in perpendicular recording media", M. Benakli, A. F. Torabi. M. L. Mallory, H. Zhou and H. N. Bertram, IEEE Trans. Magn., 37(4), p. 1564-1566, (2001).
    [PDF  ucsd only]
  202. Tape medium noise measurements and analysis", P. Luo and H. N. Bertram, IEEE Trans. Magn., 37(4), p. 1620-1623, (2001). 
    [PDF      ucsd only]
  203. "Simulation of servo position error signal in perpendicular recording", Z. Jin. H. N. Bertram and P. Luo, IEEE Trans. Magn., 37(6), p. 3977-3980, (2001). [PDF  ucsd only]

    2002
  204. "Thermally Activated Magnetization Fluctuations in Spin Valve and GMR Sensors: Mode Theory and Experimental Measurements", Z. Jin, H. N. Bertram and V. Safonov, Digest, INTERMAG 2002, p. BP-7, (May). [PDF  ucsd only]
  205. "Dynamics in Perpendicular Recording Using 3D Micromagnetic Simulation", K. Gao and H. N. Bertram, Digest, INTERMAG 2002, p. CB-9, (May). [PDF  ucsd only]
  206. "Thermal Noise, Damping Fundamentals and Mode Analysis: Application to GMR Sensors", H. N. Bertram and V. L. Safonov, Digest, INTERMAG 2002, p. EA-6, (May).
  207. "Head-Field Rise-Time Effects in Perpendicular Recording", K. Nakamoto and H. N. Bertram, Digest, INTERMAG 2002, p. EQ-2, (May).
  208. "Playback Signal in Perpendicular Recording for an Off-Centered GMR Element", B. Valcu and H. N. Bertram, Digest, INTERMAG 2002, p. EQ-8, (May).
  209. "Approaches to Evaluate Thermal Reversal of Interacting Magnetic Grains", X. Wang, H. N. Bertram, R. W. Gustafson, E. Boerner, A. Lyberatos and V. L. Safonov, Digest, INTERMAG 2002, p. EQ-9, (May).
  210. "Experimental and theoretical studies of thermal magnetization noise in GMR heads", H. N. Bertram, Z. Jin and V. L. Safonov, IEEE Trans. Magn. 38(1), p. 38-44, (2002). ( INVITED) [PDF  ucsd only]
  211. "Pulse shape, resolution and signal-to-noise ratio in perpendicular recording", B. Valcu, T. Roscamp and H. N. Bertram, IEEE Trans. Magn., 38(1), p. 288-294, (2002). (INVITED) [PDF  ucsd only]
  212. "Micromagnetic analysis of the effect of intergranular exchange on thermal stability in magnetic recording: (I) 2D isotropic longitudinal media", H. Zhou and H. N. Bertram, IEEE Trans. Magn., 38(2), p. 1405-1416, (2002). [PDF  ucsd only]
  213. "Micromagnetic analysis of the effect of intergranular exchange on thermal stability in magnetic recording: (II) Slightly oriented longitudinal media", H. Zhou and H. N. Bertram, IEEE Trans. Magn., 38(2), p. 1417-1421, (2002). [PDF  ucsd only]
  214. "Micromagnetic analysis of the effect of intergranular exchange on thermal stability in magnetic recording: (III) Perpendicular Media", H. Zhou and H. N. Bertram, IEEE Trans. Magn., 38(2), p. 1422-1428, (2002). [PDF  ucsd only]
  215. "Simulation of the off-track capability of a one Terabit per square inch recording system", Z. Jin, H. N. Bertram, B. Wilson and R. Wood, IEEE Trans. Magn., 38(2), p. 1429-1435, (2002). [PDF  ucsd only]
  216. "Experimental study of signal-dependent noise in metal particle tape", P. Luo, H. N. Bertram, B. Buchan and Z. Jin, IEEE Trans. Magn., 38(4), p. 1807-1813, (2002). [PDF  ucsd only]
  217. "Thermal magnetization noise in a thin film", V. L. Safonov and H. N. Bertram, Physical Review B, vol. 65-172417(4), (2002). [PDF  ucsd only]
  218. "Conditions for infinite reversible susceptibility as magnetic systems reach irreversible switching. H. N. Bertram and A. D. Liu, J. of Magn. and Magn. Mater. 247, p.279-296, 2002. [PDF  ucsd only]
  219. "Effect of Cr concentration gradient on the intergranular exchange in CoCr(Ta,Pt) thin films", B. Valcu and H. N. Bertram, J. Appl. Phys., 91(2), p. 764-771, (2002). [PDF  ucsd only]
  220. "Thermal induced reversal in coupled grains and elongated particles", X. Wang, H. N. Bertram and V. L. Safonov, J. Appl. Phys., 91(10), p. 6920-6922, (2002). [PDF  ucsd only]
  221. "Nonuniform thermal magnetization noise in thin films: Application to GMR heads", V. L. Safonov and H. N. Bertram, J. Appl. Phys., 91(10), p. 7279-7281, (2002). [PDF  ucsd only]
  222. "Effect of intergranular interactions on thermal energy barrier distribution on perpendicular media", H. Zhou, H. N. Bertram, and M. E. Schabes, J. Appl. Phys., 91(10), p. 8378-8380, (2002). [PDF  ucsd only]
  223. "Determination of transition shape by transition mode noise analysis", Z. Jin, P. Luo, H. N. Bertram, K. Zhang and G. H. Lin, J. Appl. Phys., 91(10), p. 8706-8708, (2002). [PDF  ucsd only]
  224. "Effect of temperature and cubic anisotropy on the switching field of cylindrical Ni particles", M. Hwang, M. Shima, C. A. Ross, C. Seberino and H. N. Bertram, J. Appl. Phys., 92(2), p. 1018-1023, (2002). [PDF  ucsd only]
  225. "Thermal-dynamic reversal of fine magnetic grains with arbitrary anisotropy axes orientation", X. Wang, H. N. Bertram and V. L. Safonov, J. Appl. Phys., 92(4), p. 2064-2072, (2002). [PDF  ucsd only]
  226. "Field and temperature dependent attempt frequency for dynamic-thermal reversal of magnetic grains", X. Wang and H. N. Bertram, J. Appl. Phys., 92(8), p. 4560-4570, (2002). [PDF  ucsd only]
  227. "Effect of crystallographic orientation on grain size distribution", B. Valcu, Y. Takahashi, H. N. Bertram, J. Appl. Phys., 92(10), p. 6094-6098. (2002). [PDF  ucsd only]
  228. "Write field analysis in perpendicular recording using three-dimensional micromagnetic simulation", K. Gao and H. N. Bertram, J. Appl. Phys., 92(10), p. 8369-8371, (2002). [PDF  ucsd only]
  229. "Fast switching in single domain particle under sub Stoner-Wohlfarth switching fields", K. Gao, E. Boerner and H. N. Bertram, Applied Physics Letters, 81(21), p. 4008-4010, (2002). [PDF  ucsd only]
  230. "Analytic perpendicular-recording model for transition parameter and NLTS", K. Nakamoto and H. N. Bertram, The Magnetic Society of Japan, vol. 27, no. 2, p. 79-85, (2002). [PDF  ucsd only]
  231. "3D micromagnetic simulation of write field rise time in perpendicular recording", K. Gao and H. N. Bertram, IEEE Trans. Magn., 38(5), p. 2063-2065, (2002). [PDF  ucsd only]
  232. "Effect of head-field rise-time in perpendicular recording", K. Nakamoto and H. N. Bertram, IEEE Trans. Magn., 38(5), p. 2069-2071, (2002). [PDF  ucsd only]
  233. "3D analysis of the playback signal in perpendicular recording for an off-centered GMR element", B. Valcu and H. N. Bertram, IEEE Trans. Magn., 38(5), p. 2081-2083, (2002). [PDF  ucsd only]
  234. "Thermal decay of interacting grains in perpendicular thin film media", X. Wang, H. N. Bertram, E. Boerner, A. Lyberatos and V. L. Safonov, IEEE Trans. Magn., 38(5), p. 2084-2086, (2002). [PDF  ucsd only]
  235. "Experimental measurements and analysis of thermal magnetization noise in GMR sensors", Z. Jin, H. N. Bertram and V. L. Safonov, IEEE Trans. Magn., 38(5), p. 2265-2267, (2002). [PDF  ucsd only]
  236. "Thermal magnetization noise, damping fundamentals and mode analysis: Application to a thin film GMR sensor", H. N. Bertram, V. L. Safonov and Z. Jin, IEEE Trans. Magn., 38(5), p. 2514-2519, (2002). (INVITED) [PDF  ucsd only]
  237. "Write field analysis and write pole design in perpendicular recording", K. Gao and H. N. Bertram, IEEE Trans. Magn., 38(5), p. 3521-3527, (2002). [PDF  ucsd only]
  238. "Magnetic recording configuration for densities beyond 1 Tb/in2 and data rates beyond 1 Gb/s", K. Gao and H. N. Bertram, IEEE Trans. Magn. 38(6), p. 3675-3683, (2002). [PDF  ucsd only]
  239. "Physical interpretation of hysteresis loops: Micromagnetic modeling of fine particle magnetite", L. Tauxe, H. N. Bertram and C. Seberino, Geochem. Geophys. Geosyst., 3(10), p. 1055-1076, (2002). [PDF  ucsd only]
  240. "Magnetic properties of arrays of electro deposited nanowires", C.A. Ross, M. Nwang, M. Shima, H. I. Smith, M. Farhoud, T. A. Savas, W. Schwarzacher, J. Parrochon, W. Escoffier, H. N. Bertram, F. B. Humphrey and R. Redjdal, J. of Magn. and Magn. Mater., 294, p. 200-207, (2002). [PDF  ucsd only]

    2003
  241. "Effects of Distributions in Tilted and Conventional Perpendicular Recording", K-Z. Gao and H. N. Bertram, Digest, NAPMRC 2003, p. 39, (January).
  242. "Transition jitter estimates in tilted and conventional perpendicular recording media at 1 Tbit/in2", K. Gao and H. N. Bertram, IEEE Trans. Magn., 39(2), p. 704-709, (2003). [PDF  ucsd only]
  243. "PRML channel performance under the influence of medium noise in tape recording system", P. Luo, Z. Jin and H. N. Bertram, IEEE Trans. Magn., 39(2), p. 1072-1080, (2003). [PDF  ucsd only]
  244. "Analyses of the effect of head imaging on medium demagnetization field in perpendicular recording", H. Zhou, K. Gao and H. N. Bertram, J. Appl. Phys., 93(10), p. 6537-6539, (2003). [PDF  ucsd only]
  245. "Energy surface model of single particle reversal in sub-Stoner-Wohlfarth switching fields", K. Gao, E. Boerner, and H. Neal Bertram, J. Appl. Phys., 93(10), p. 6549-6551, (2003). [PDF  ucsd only]
  246. "Nonlinear microscopic relaxation of uniform magnetization precession", V. L. Safonov and H. N. Bertram, J. Appl. Phys., 93(10), p. 6912-6914, (2003). [PDF  ucsd only]
  247. "Simple transition parameter expression including grain size and intergranular exchange", X. Wang and H. N. Bertram, J. Appl. Phys., 93(10), p. 7005-7007, (2003). [PDF  ucsd only]
  248. "Anomalously large damping in magnetization reversal", X. Wang and H. N. Bertram, J. Appl. Phys., 93(10), p. 7396-7398, (2003). [PDF  ucsd only]
  249. "Track edge effect in tilted and conventional perpendicular recording", K. Gao, X. Wang and H. N. Bertram, J. Appl. Phys., 93(10), p. 7840-7842, (2003). [PDF  ucsd only]
  250. "Thermal stability of coupled ferromagnetic and superparamagnetic particles", V. L. Safonov and H. N. Bertram, J. Appl. Phys., 93(10), p. 8474-8476, (2003). [PDF  ucsd only]
  251. "Linear stochastic magnetization dynamics and microscopic relaxation mechanisms", V. L. Safonov and H. N. Bertram, J. Appl. Phys., 94(1), p.529-538, (2003). [PDF  ucsd only]
  252. "Micromagnetic study of the transition parameter and position jitter in perpendicular recording", Y. Shimizu and H. N. Bertram, IEEE Trans. Magn., 39(3), p. 1846-1850, (2003). [PDF  ucsd only]
  253. "An analytical model for the cross-track correlation length including inter-granular interactions", Z. Jin, X. Wang and H. N. Bertram, IEEE Trans. Magn. 39(5), p. 2603-2605, (2003). [PDF  ucsd only]
  254. "Measurements and analysis of transition noise in perpendicular media", C. Fu, Z. Jin, H. N. Bertram, Y. Wu and D. Guarisco, IEEE Trans. Magn. 39(5), p. 2606-2608, (2003). (See #266 for Errata) [PDF  ucsd only]
  255. "Energy barrier and effective thermal reversal volume in columnar grains", H. Forster, N. Bertram, X. Wang, R. Dittrich and T. Schrefl, J. of Magn. and Magn. Mater, 267, p. 69-79,(2003). [PDF  ucsd only]

    2004
  256. "Local relaxation mechanisms and collective stochastic dynamics", H. N. Bertram and X. Wang, J. of Magn. and Magn. Mater, 271, p. 254-269, (2004) [PDF  ucsd only]
  257. "Quasi-analytical calculation of thermal magnetization fluctuation noise in GMR sensors", Z. Jin, H. N. Bertram and V. Safonov, IEEE Trans. Magn., 40(3), p. 1712-1722, (2004). [PDF  ucsd only]
  258. "Analysis of DC noise in thin film media", H. N. Bertram, M. Marrow, J. Ohno, C. Fu, J. K. Wolf, IEEE Trans. Magn., 40(4), p. 2311-2313, (2004).  [PDF  ucsd only]
  259. "Soft underlayer magnetization dynamics", B. Valcu and H. N. Bertram, IEEE Trans. Magn., 40(4), p. 2377-2379, (2004).  [PDF  ucsd only]
  260. "Thermal reversal of elongated ferromagnetic particles misoriented to the applied field", D. Goll and H. N. Bertram, IEEE Trans. Magn., 40(4), p. 2416-2418, (2004). [PDF  ucsd only]
  261. "Thermal decay and erasure process for perpendicular recording at 1Tb/in2", K. Z. Gao, M. Williams, H. Zhou, J. Fernandez-de-Castro and H. N. Bertram, IEEE Trans. Magn., 40(4), p. 2449-2451, (2004). [PDF  ucsd only]


    2005-                                                      Back to Top

  262. "Technique to obtain head-medium magnetic spacing in a disk drive", C. Fu, A. Takeo and H. N. Bertram, J. Appl. Phys., 97, p. 10P107(1-3), (2005). [PDF  ucsd only]
  263. "DC noise enhancement due to correlations between grain size and switching field", M. Marrow and H. N. Bertram, J. Appl. Phys., 97, p. 10N101(1-3), (2005). [PDF  ucsd only]
  264. "Pulses shape, resolution and signal-to-noise ratio in patterned media recording", A. Takeo and H. N. Bertram, J. Appl. Phys., 97, p. 10N104(1-3), (2005). [PDF  ucsd only]
  265. "Micromagnetic study of the switching fields in polycrystalline magnetic thin-film media", K-Z. Gao, J.Fernandez-de-Castro, and H. N. Bertram, IEEE Trans. Magn., 41(11), p.4236-4241, (2005). [PDF  ucsd only]
  266. Correction to: "Measurements and analysis of transition noise in perpendicular media", C. Fu, Z. Jin, H. N. Bertram, IEEE Trans. Magn. 41(11) p. 4371 (2005). [PDF  ucsd only]
  267. "Minimum particle volume of tilted and composite media considering magneto-static interactions" A. Takeo & H. N. Bertram, Digest IEEE International Magnetics Conference, 2005. INTERMAG, p.1363-1364 (2005). [PDF  ucsd only]
  268. "A technique to obtain head-medium magnetic spacing in a disk drive", C. Fu, A. Takeo and H. N. Bertram, J. Appl. Phys. 97, 10P107 (2005). [PDF  ucsd only]
  269. "Fluctuation-dissipation considerations and damping models for ferromagnetic materials", H. N. Bertram and V. L. Safonov, Physical Review B-Condensed Matter, 71(22), p. 224402-1-5, (2005).
    [PDF  ucsd only]


    2006
  270. "Transition shape analysis from medium noise measurements", H. N. Bertram, A. Takeo, Z. Jin and C. Fu, IEEE Trans. Magn., 42(5), p.1620-1625, (May 2006). [PDF  ucsd only]
  271. "Design parameter optimization for perpendicular magnetic recording systems", P. Chaichanavong, H. N. Bertram, P. H. Siegel, IEEE Trans. Magn., 42(10), p. 2549-2554, (October 2006).
    [PDF  ucsd only]
  272. "Magnetic ground states and the role of vortices in ferromagnetic hollow nanosphers", D. Goll, S. Macke, A. E. Berkowitz, and H. N. Bertram, Physica B, 372 (1-2), p. 282-285, (2006).
    [PDF  ucsd only]


    2007
  273. "Design curves and information-theoretic limits for perpendicular recording systems", Z. Wu, P. H. Siegel, H. N. Bertram, and J. K. Wolf, IEEE Trans. Magn., 43(2), p. 721-726, (February 2007).
    [PDF  ucsd only]
  274. "Thermal reversal of exchange spring composite media in magnetic fields", D. Goll, S. Macke, H. N. Bertram. Applied Physics Letters, 90, 172506-1-3 (April 2007). [PDF  ucsd only]
  275. "Energy barriers in composite media grains," H. N. Bertram and B. Lengsfield. IEEE Trans. Magn., 43(6), p. 2145-2147, (June 2007).[PDF  ucsd only]
  276. "Magnetization reversal in patterned media," V. Lomakin, B. Livshitz and H. N. Bertram. IEEE Trans. Magn., 43(6), p. 2154-2156, (June 2007). [PDF  ucsd only]
  277. "Precessional reversal in exchange-coupled composite magnetic elements," B. Livshitz, A. Inomata, H.N. Bertram, and V. Lomakin, Applied Physics Letters, 91(18), p. 182502, (October 2007). [PDF  ucsd only]

    2008
  278. "Dual-layer patterned media “ledge” design for ultrahigh density magnetic recording,” V. Lomakin, R. Choi, B. Livshitz, S. Li, A. Inomata, and H.N. Bertram, Applied Physics Letters, 92( 2), p. 022502, (January 2008). [PDF  ucsd only]
  279. “A new read channel model for patterned media storage,”S. Karakulak, P. H. Siegel, J. K. Wolf, and H. N. Bertram, IEEE Trans. Magn., 44(1), pp. 193-197, (January 2008). [PDF  ucsd only]

  280. " Nucleation fields in composite medium grains," H.N. Bertram, M.E. Schabes, V. Lomakin, and B. Livshitz, Journal of Applied Physics, 103(7), p. 07F508, (April 2008), [PDF  ucsd only]

  281. "Fast precessional reversal in perpendicular composite patterned media," B. Livshitz, R. Choi, V. Lomakin, A. Inomata, H.N. Bertram, Journal of Applied Physics, 103(7), p. 07C516, (April 2008),
    [PDF  ucsd only]

     PENDING                                                       Back to Top

Research Group

Alumni:

Student Name: Alexander Barany

Dissertation: Noise and Non-Linear Recording Phenomena in Thin Metallic Films [Abstract only]

Degree: Ph.D.

Year: 1988

Student Name: Eric Boerner

Dissertation: Simulation of Thermal Decay and Dynamic Relaxation in Ferromagnetic Materials [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 2000

Student Name: Eric Champion

Dissertation: Digital Magnetic Recording Systems Utilizing Magnetoresistive (Mr) Playback Technology: Theoretical Studies
[Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 1997

Student Name: Kaizhong Gao

Dissertation: Optimization of Write Heads and Media for Ultra High Density and Data Rate Magnetic Recording [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 2002

Student Name: Zhen Jin

Dissertation: Experimental and Theoretical Studies of Noise and Off-Track Issues in Magnetic Recording Systems [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 2002

Student Name: Gang Lin

Dissertation: Experimental Studies of Nonlinearities, Erasure and Noise in Magnetic Recording Channel [Abstract only]  

Degree: Ph.D.

Year: 1994

Student Name: Alfred Liu

Dissertation: Numerical Modeling of Granular Magnetic Materials

Degree: Ph.D. [Abstract]   [PDF  ucsd only]

Year: 2000

Student Name: Peng Luo

Dissertation: Experimental and Theoretical Studies of Particulate Tape Medium Noise in High-Density Magnetic Recording Systems [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 2001

Student Name: Qingzhi Peng

Dissertation: Microstructural Dependence of Magnetization Process in Thin Film Recording Media [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 1997

Student Name: Gene Sandler

Dissertation: Computational Analyses of Magnetization Dynamics in Thin Film Write Heads [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 1998

Student Name: Manfred Schabes

Dissertation: Micromagnetics of Small Ferromagnetics Particles
[Abstract only]

Degree: Ph.D.

Year: 1989

Student Name: Christian Seberino

Dissertation: Computational Micromagnetic Study of Particulate Media Hysteresis and Recording [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 2000

Student Name: Thomas Silva *

Dissertation: A Scanning Near-Field Optical Microscope With Magneto - Optic Kerr Effect Contrast for the Imaging Of Magnetic Domains With 200 A Resolution [Abstract]  [PDF  ucsd only]

Degree: Ph.D.

Year:  1994

Student Name: Bogdan Valcu

Dissertation: Studies in Perpendicular Magnetic Recording [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 2004

Student Name: David Wachenschwanz

Dissertation: A Study of High Frequency and Saturation Effects in Magnetic Recording Heads

Degree: M.S.

Year: 1990

Student Name: Xiaobin Wang

Dissertation: Studies on Dynamic Thermal Reversal and Transition Jitter in Magnetic Materials [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 2003

Student Name: Xinzhi Xing

Dissertation: Noise and Nonlinearities in Digital Magnetic Recording Systems [Abstract]   [PDF  ucsd only]

Degree: Ph.D.

Year: 1998

Student Name: Samuel Yuan

Dissertation: Micromagnetics of Domains and Walls in Soft Ferromagnetic Materials [Abstract only]

Degree: Ph.D.

Year: 1992

Student Name: Yun Zhang

Dissertation: MR Playback Characteristics and Thermal Stability of Thin Film Media in High-Density Magnetic Recording Systems [Abstract] [PDF  ucsd only]

Degree: Ph.D.

Year: 1999

Student Name: Hong Zhou

Dissertation: Micromagnetic Analyses of Effects of Intergranular Magnetostatic and Exchange Interactions on Signal-to-Noise Ratio and Thermal Stability in Hard Disk Drive Recording Media [Abstract] [PDF  ucsd only]

Degree: Ph.D.

Year: 2001

Student Name: Jian-Gang Zhu

Dissertation: Interface Phenomena in Magnetic Thin Films
[Abstract only]  [PDF  ucsd only]

Degree: Ph.D.

Year: 1988

Co-Chair Advisor