Spin-glass ordering in a spinel ferrite,Mg(Al, Fe)2O4

Abstract

Non-linear susceptibility (χnl) measurements onMgAl1.4Fe0.6O4 show spin-glass ordering in a cubicspinel ferrite, for the first time. The ordering gives a peak inthe temperature dependence of χnl, which shows that thespin ordering is a cooperative phase transition. The values of thecritical exponents, obtained from χnl as the temperatureapproaches the transition temperature, are found to lie in the rangeobtained from measurements on other spin glasses. We alsoinvestigate the static and dynamical effects of the spin-glassordering on Mössbauer spectra. Dynamical spin freezing as aresult of spin-glass ordering is observable in Mössbauer spectra.