Thermal stability and micromagnetic properties of high-density CoCrPtTa longitudinal media

Micromagnetic and magnetic force microscopy (MFM) studies of high-density longitudinal media are carried out in relation to recording performance and thermal stability. The MFM technique is demonstrated to provide information on not only micromagnetics but also on recording parameters such as signal and signal-to-noise ratio comparable to those obtained using a read head. Annealing experiments are performed on wide (3.5 mu m) and narrow (0.8 mu m) track bits written onto CoCrPtTa to accelerate the thermal reversal process. The written marks are predicted to be unstable for the measured medium magnetic anisotropy energy. However, comparison of the MFM images of the same patterns before and after the anneal reveals no significant degradation with annealing up to 490 K for 12 h. For more extreme annealing conditions, degradation is shown to start not only at the track edges but also between the bits.