Néel temperature enhancement in nanostructured nickel zinc ferrite

Abstract

The Néel temperature of Ni0.5Zn0.5Fe2O4 spinel ferrite increases significantly from 538K in the bulk state to 592K when the grain size is reduced to 16nm by milling in a high-energy ball mill. This has been attributed to an increase in the AB superexchange interaction strength due to a possible enhancement in the magnetic ion concentration in the A-site on milling, as is evident from extended x-ray absorption fine structure and in-field Mössbauer measurements.