Magnetization and thermal stability studies on laminated antiferromagnetically coupled (LAC) media

This paper summarizes the magnetization and thermal stability studies on laminated antiferromagnetically coupled (LAC) media. Magnetization studies indicate that the M_rδ reduction in LAC media arises due to the competition of antiferromagnetic coupling constant (J), magnetization (M₂), anisotropy constant (K_u2), thickness (t₂) of the bottom layer, and the thermal energy (k_BT). At larger time-scales of measurement, thermal energy helps to obtain antiferromagnetic configuration at remanence, even for small values of J. Thermal stability studies indicate that the stability factor (SF=K_uV/k_BT) of LAC media increases with increasing the thickness of the stabilizing layer. However, it is pointed out in detail for the first time that this increase could arise from different sources, such as the absence of the dead-layer effect. The authors also propose a new inverted structure, which is suitable for understanding the thermal stability in LAC media.