Study of Additive Effects on the Structural, Magnetic Properties and Mössbauer Spectroscopic Analysis of Cobalt Cadmium Ferrites

Abstract

The present work is focused on the structural, magnetic properties and Mössbauer spectroscopic analysis of Co-Cd ferrites. The ferrite samples of the compositions Co1-x CdxFe2O4 (where x=0.0, 0.1, 0.3, 0.4 and 0.5) were prepared by using the solid state reaction technique. The phase identification was carried out by using the X-ray diffraction (XRD). The XRD analysis revealed that all the samples were found to crystallize in single phase cubic spinel structure. The lattice constant of Co1-x CdxFe2O4 ferrites increases linearly with the increase Cd-content, followed Vegard's law. Bulk density and X-ray density significantly increase with the increase of Cd- content. Curie temperature (Tc) decreases almost linearly with increasing Cd-content. Initial permeability was found to increase with Cd-content at constant sintering temperature which may be attributed to enhanced density and reduced anisotropy energy as well as increase in grain size of the studied samples. The permeability spectrum with frequency follows the Snoek's limit. Saturation magnetization (Ms) increases with Cd-content with high value of 49 emu/g for x =0.5 emu/g. All Co-Cd ferrites have been investigated using Mössbauer spectroscopy. The Mössbauer measurements were performed with a conventional constant acceleration spectrometer at room temperature in transmission geometry, using 57Co in a rhodium matrix. The velocity scale of a thin 57Fe sample and the isomer shifts are given relative to the centroid of the spectrum. The isomer shifts of Fe atoms in all Co-Cd ferrites sample behave trivalent ions. The spectrum for the Co1-x CdxFe2O4 ferrites consists of six lines which are broad as compared with Mössbauer spectrum of a pure 57Fe samples in the form of a thin foil up to x = 0.5. After x ≥ 0.6, Co-Cd ferrites consists a paramagnetic doublet, reflecting a severe chemical disorder. One of the magnetic signals is a sextet typical of those associated with a good magnetic order at room temperature.