Investigation of Room Temperature Mössbauer Spectroscopy and Initial Permeability Properties of Al3+ Substituted Cobalt Ferrites

Abstract

In the present work, Al[Formula: see text] substituted cobalt ferrites (CoFe[Formula: see text]AlxO4, [Formula: see text], 0.4, 0.6, 0.8) have been synthesized via standard solid-state reaction technique. The incorporation of Al[Formula: see text] ions in cobalt ferrite has been shown to play an important role in modifying the magnetic properties. The room temperature (300[Formula: see text]K) [Formula: see text]Fe Mössbauer spectra reveals that the studied samples show two characteristic ferromagnetic zeeman sextets at A and B-sites at lower Al[Formula: see text] ion concentration (i.e., up to [Formula: see text]). However, a paramagnetic relaxation has been noted for higher Al[Formula: see text] substitution (for [Formula: see text] and 0.8) samples. The dependence of the Mössbauer parameters such as isomer shift, quadrupole splitting, line width and magnetic hyperfine field on Al[Formula: see text] ion concentration has also been noted. The variations in initial permeability over a wide frequency range (125[Formula: see text]kHz to 30[Formula: see text]MHz) at 300[Formula: see text]K have been recorded. The fairly constant values of initial permeability and the low values of the relative loss factor of the order of 10[Formula: see text] to 10[Formula: see text] over the wide frequency range are the important findings of the present work. The observed low values of relative loss factor at high frequencies suggest that the studied ferrites are promising materials to be used in microwave applications.