R&D: Hysteresis Loops of Recording Media Grains Under Influence of High Frequency Fields

IEEE Xplore has published, in 2022 IEEE 33rd Magnetic Recording Conference (TMRC) proceedings, an article written by Simon John Greaves, RIEC, Tohoku University, Sendai, Japan, and Yasushi Kanai, IEE, Niigata Institute of Technology, Kashiwazaki, Japan.

Abstract: “A potential technology for use in future hard disk drives is microwave-assisted magnetic recording (MAMR). In a MAMR drive a spin-torque oscillator (STO) is integrated into the write head and applies a high frequency (HF) magnetic field to the recording medium along with the field from the write head. The HF field reduces the switching field of the medium, allowing media with higher uniaxial anisotropy to be used. As the write head moves over the recording medium the HF field seen by the medium grains changes from elliptical to circular to linear and back again. In this work the influence of circular, elliptical and linear HF fields on recording media was examined by calculating hysteresis loops for single and multiple grains.“