High susceptibility of soft magnetic composites above MHz range

We present a susceptibility model of bi-anisotropy soft magnetic composites (BSMCs) consisted of bi-anisotropy single-domain particle (BSDP) with a unified anisotropy which is a both polar and azimuthal angles related bi-anisotropy. We find that the product of initial susceptibility and resonance frequency in the BSDP is beyond Snoek's law. We derive the susceptibility of BSMCs further based on that of BSDP and find it is related to the orientations of both magnetization in static state and easy magnetization plane. More importantly, the maximum susceptibility of BSMCs is the same as that of a BSDP when the magnetizations in static state of BSDPs are oriented in one direction or plane. Our model provides an approach to improve the susceptibility of BSMCs.