Simulation of thermal stability of a keepered medium with a soft magnetic underlayer

Two-dimensional finite element numerical read/write simulation at finite temperatures was performed on a keepered medium (KM) with a soft magnetic underlayer and a thin-film head system. The M-H model for the recording layer is a so-called Stoner-Wohlfarth model modified by taking account of a thermal switching of each particle using a Monte Carlo method. The output voltage reductions at 300 K due to the thermal fluctuation for the KM with the recording layer of M_r=680 kA/m, t=36 nm and H_c=159 kA/m, K_uV/k_BT=30 and 50 and with the optimized keeper layer were calculated to be 9.7% for K_uV/k_BT=30 and 3.2% for K_uV/k_BT=50, though those for the media without the keeper layer were 20.4% and 12.5%, respectively. In conclusion, the KM may be a hopeful candidate for improving the thermal stability in a high density magnetic recording