Model of thermal erasure in neighboring tracks during thermomagnetic writing

A method is presented for the calculation of the thermal erasure of the recorded information in neighboring tracks and implemented for heat-assisted magnetic recording on FePt granular thin films with high perpendicular anisotropy. The thermal erasure in neighboring tracks decays exponentially with distance from the recording head. It is strongly dependent on the heating, grain size, and anisotropy but the write field has a relatively small effect. The track width is dependent primarily on the temperature profile of the laser beam. Secondary effects arising from the write field, anisotropy, intergranular magnetostatic, and exchange coupling are also considered. A more square shaped temperature profile of the laser beam results in substantial improvement in recording properties; enhancement of read signal and sharpness of the magnetic transition and reduction of transition jitter and lubricant loss.

[1]  J. W. Brown.  Thermal Fluctuations of a Single-Domain Particle , 1963 .

[2]  W. Coffey,et al.  EFFECT OF AN OBLIQUE MAGNETIC FIELD ON THE SUPERPARAMAGNETIC RELAXATION TIME. II. INFLUENCE OF THE GYROMAGNETIC TERM , 1998 .

[3]  H. Neal Bertram,et al.  Theory of Magnetic Recording , 1994 .

[4]  H. Bertram,et al.  Micromagnetic analysis of the effect of intergranular exchange on thermal stability in magnetic recording. III. Perpendicular media , 2002 .

[5]  H. Pfeiffer,et al.  Determination of anisotropy field distribution in particle assemblies taking into account thermal fluctuations , 1990 .

[6]  Masud Mansuripur,et al.  The Physical Principles of Magneto-optical Recording , 1995 .

[7]  Hans Jurgen Richter,et al.  Dynamic coercivity effects in thin film media , 1998 .

[8]  K. Guslienko,et al.  Thermal stability of the magnetization following thermomagnetic writing in perpendicular media , 2003 .

[9]  K. Ashar,et al.  An analytical three-dimensional field model of a perpendicular recording head , 1988 .

[10]  E. Wohlfarth,et al.  A mechanism of magnetic hysteresis in heterogeneous alloys , 1948, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[11]  K.T. Chau,et al.  Design of permanent magnets to avoid chaos in PM synchronous machines , 2003, Digest of INTERMAG 2003. International Magnetics Conference (Cat. No.03CH37401).

[12]  J. Hoinville.  Micromagnetic modeling of the thermomagnetic recording process , 2001 .

[13]  Non-Arrhenius behavior in single domain particles , 1998 .

[14]  H. N. Bertram,et al.  Magnetic recording configuration for densities beyond 1 Tb/in/sup 2/ and data rates beyond 1 Gb/s , 2002 .

[15]  Margaret Evans Best,et al.  High K/sub u/ materials approach to 100 Gbits/in/sup 2/ , 2000 .

[16]  Riccardo Borghi,et al.  Correspondence between super-Gaussian and flattened Gaussian beams , 1999 .

[17]  R. L. Weber,et al.  The Physical Principles of Magnetism , 1967 .

[18]  S. R. Cumpson,et al.  A hybrid recording method using thermally assisted writing and flux sensitive detection , 2000 .

[19]  Kelly,et al.  Magnetocrystalline anisotropy and orbital moments in transition-metal compounds. , 1991, Physical review. B, Condensed matter.

[20]  H. Muraoka,et al.  Thermal agitation of magnetization in CoCrPt perpendicular recording media , 2001 .

[21]  Michael F. Toney,et al.  Temperature dependent magnetic properties of highly chemically ordered Fe55−xNixPt45L10 films , 2002 .