Ferrimagnetic resonance of manganese ferrites with iron excess

Abstract.

Ferrimagnetic resonance linewidths of polycrystalline and single crystal manganese ferrites, Mn_xFe_3-xO₄ with x<1.0, were measured at 8.9 GHz in the range 77–320 K. Conductivity measurements were carried out from 100 Hz to 40 MHz. The behavior of the ferrimagnetic resonance linewidth and of the resonance field was different from that obtained for manganese ferrites with x=1. These differences are attributed to the presence of a resonance mode in addition to the uniform resonance mode. The variation of the skin depth as a function of the temperature and the high conductivity of the samples is responsible for the appearance of this extra mode. This assumption is corroborated by the analysis of the asymmetry of the absorption curve.