Micromagnetic calculation of HAMR media hysteresis loop at experimental time scale

Media hysteresis loop is a fundamental measurement to experimentally characterize the magnetic properties of a thin film media used in magnetic recording. For theoretical study, it is also an important tool to validate theoretical models and calibrate model parameters. However, direct calculation of hysteresis loop at experimental time scale is often difficult because of the very slow sweep rate (∼50–1000Oe/sec) used in VSM or Polar Kerr measurements. Micromagnetic based simulations (LLG, LLB) are very slow and impractical at such slow sweep rates. Heat assisted magnetic recording (HAMR)[1,2] poses another challenge due to the need to understand media magnetics/hysteresis loops at various temperatures and to assess its impact to recording performance.