Memory Erasure and Write Field Requirements in HAMR Using L1(o)-FePt Nanoparticles

作者：Lyberatos Andreas^*; Weller Dieter; Parker Gregory J

来源：IEEE Transactions on Magnetics, 2014, 50(11): 2104304.

DOI：10.1109/TMAG.2014.2323171

• Heat-assisted magnetic recording (HAMR)
• magnetic particles
• magnetic switching
• magnetization reversal

The write field requirements in heat-assisted magnetic recording (HAMR) using FePt media are studied using an atomistic model. Langevin dynamics simulations of laser-induced thermal demagnetization and magnetization recovery are performed on a single L1(o)-ordered FePt grain. We show that the minimum heat temperature for thermal overwrite of information is a cooling rate-dependent temperature T-o, larger than the Curie temperature of the grains. If T-o is exceeded, memory effects can be neglected in HAMR since the characteristic pulse time is long compared with the mean first passage time of thermal demagnetization. The minimum write field H-w to attain sufficiently high thermoremanence M-Z = 0.9M(S) is then independent of the heating process. We study the variation of H-w with cooling rate, damping, field orientation, and grain size L, and explore the phase space of the parameters H, T, and L, also resulting in thermal stability of the recorded information during storage.

• 出版日期2014-11