Effective Switching Field Distribution Evaluation Using Saturation Field in Minor Loop*

A new method for evaluating the switching field distribution (SFD) in perpendicular magnetic recording media is proposed using the saturation magnetic field of a minor loop, H_s^minor. In this method, the switching fields of focused reversal magnetic grains are measured with all magnetic moments in other domains saturated in the upward direction. Thus, the proposed SFD evaluation is not affected by variety of domain structure, and reveals tails of distribution. Using the proposed method, the SFD for various granular media was evaluated.