Ferromagnetic Resonance of Electrically Conductive Manganese Ferrites

Abstract

Resonance experiments have been performed between 77–350 K at 9.3 GHz on single crystal spheres of manganese ferrite of low resistivities (0.1∼0.3 Ω cm at room temperature). The linewidth shows a maximum at a temperature from 100 K to 200 K, with a marked dependence upon the sample size as well as upon the resistivity of specimen. A characteristic deviation of the resonance field in ⟨111⟩ from that expected by Kittel’s formula is also noted. Detailed description is given to show the observed results to be attributable to an eddy current effect rather than due to the so-called slow or fast relaxation mechanisms. The linewidth maximum is interpreted to occur in a temperature region over which the excitation of resonant mode varies from “surface type” to “volume one” corresponding to the change in skin depth.