Spin‐Wave Contribution to the Deviation of the Magnetization from Saturation

摘要

A first‐order macroscopic spin‐wave Hamiltonian is used to describe and calculate the deviation of the magnetization from saturation for materials with a uniaxial magnetic anisotropy perpendicular to an applied magnetic field. The calculations predict a spin‐wave deviation from saturation prior to the onset of any actual rotation of the magnetization. When the magnetic anisotropy creates an easy axis of magnetization, the spin‐wave deviations from saturation occur, for a decreasing applied field, at a larger field than the nucleation field given by the variational and/or micromagnetic approaches. When the anisotropy creates a hard axis of magnetization, spin‐wave deviations from saturation occur; whereas, the variational and micromagnetic approaches predict no deviation from saturation for finite fields in this case. It is concluded that spin‐wave contributions to the deviation from saturation are important.