Information Stability in Heat-Assisted Magnetic Recording

Abstract

  The thermal stability factor K_umV_m /kT and the anisotropy constant ratio K_u /K_bulk necessary for 10 years of archiving in heat-assisted magnetic recording of 2 Tbpsi are evaluated by employing a bit error rate calculation using a grain error probability P. Although the attempt frequency f₀ in P is a function of the Gilbert damping constant, the Curie temperature, K_u /K_bulk , the grain volume, and temperature, f₀ can be treated as a constant. The Gilbert damping constant and the Curie temperature variation are parameters with little impact. On the other hand, the grain size variation, the grain number per bit n, the mean Curie temperature T_cm , and the storage temperature T are parameters with a strong impact on bit error rate. Although K_umV_m /kT decreases as n increases due to a statistical problem, a larger K_u /K_bulk is necessary as n increases due to a smaller grain size. A larger K_u /K_bulk is also necessary as T_cm decreases. The bit error rate increases rapidly as T increases.