抄録
By means of an AC susceptibility method spin relaxation in MnFe2O4 has been studied. Non-exponential relaxation has been observed near Tc in the paramagnetic region. The temperature dependence of relaxation time τm=χ′⁄(ωχ″), calculated assuming monodispersive relaxation, shows no special anomaly at T=Tc. These experimental results are analyzed within a framework of Nishikawa’s theory which takes into account nonlinear effect in spin relaxation process. The temperature dependence of the nonlinear parameter ξ, representing a measure of the strength of the nonlinearity, is obtained. The nonlinear parameter ξ increases as temperature approaches Tc and has a maximum at T=Tc. It is found that the nonlinear effect masks the anomaly of the relaxation time at T=Tc.
