The observation of the contribution of longitudinal susceptibility to the frequency of the soft magnetoresonance mode in SmFeO3

The behavior of the spectrum of the soft magnetoresonance mode in samarium orthoferrite was experimentally and theoretically studied in the region of the Γ 4 ↔Γ 24 orientation phase transition induced by an external magnetic field. The special features of this behavior can be explained by the relative contributions of interaction between ferrite subsystems and longitudinal susceptibility. It is also shown that the contribution of longitudinal susceptibility to the gap of the soft magnetoresonance mode in samarium orthoferrite can also be substantial in low fields; that is, in the vicinity of spontaneous orientation phase transitions. This is explained by the occurrence of spontaneous orientation phase transitions in samarium orthoferrite at high temperatures, at which longitudinal susceptibility is comparable in magnitude with transverse susceptibility.