Magnetic properties of In 3+ and Cr 3+ substituted Mg–Mn ferrites

Abstract

Two series of magnesium–manganese ferrites, viz., Mg 0.9Mn 0.1In x Fe 2− x O 4 and Mg 0.9Mn 0.1Cr y Fe 2− y O 4 have been prepared using conventional ceramic technique. Magnetic properties such as saturation magnetization ( M s), Curie temperature ( T c), initial permeability ( μ i), and magnetic loss factor (tan δ), of the above series of samples are presented in this paper. M s value increases slightly up to a certain concentration of indium ions thereafter it decreases, while in the case of Cr-samples saturation magnetization decreases steadily. The Curie temperature is observed to fall with increasing concentrations of both indium and chromium. The observed variations in T c and M s values are explained on the basis of exchange interactions. It is found that compared with Cr 3+ ions, In 3+ ions play more significant role in enhancing the initial permeability. The magnetic loss factor values lie in the range of 0.15–0.75 within the frequency range of 10 kHz–10 MHz. Explanation for the observed variation in μ i and tan δ with the increasing concentrations of indium and chromium are given.