Coercivity angular dependence in longitudinal thin film media

Abstract

Computer simulation study of coercivity out-of-plane angular dependence in thin film longitudinal recording media combined with experimental measurements is presented. A theoretical model developed for studying micromagnetic processes in polycrystalline thin films was utilized for the calculations. Films with crystalline easy axes of the grains randomly oriented in three dimensions as well as in the film plane are investigated. The coercivity angular dependence is analyzed by varying magnetostatic and intergranular exchange interactions broad ranges. The coercivity angular dependence is characterized by two quantities: the angular position of the coercivity maximum and the normalized difference between the maximum coercivity and in-plane coercivity. The former quantity exhibits significantly different behavior with separately varying the magnetostatic interaction strength and intergranular exchange coupling. The difference may allow us to distinguish the two types of interactions and it may allow us to determine the crystalline anisotropy constant and an effective intergranular exchange coupling strength in the film simultaneously from experimental measurements. Specifically designed experiments are carried out to verify the theoretical calculations. Reasonable agreements between the calculations and experimental measurements are obtained.