Compositional dependence of magnetization reversal mechanism, magnetic interaction and Curie temperature of Co1−xSrxFe2O4 spinel thin film

Abstract

Co1−xSrxFe2O4, (x varies from 0 to 0.5 in a step of 0.1) nanoparticles were formed by means of sol–gel processing method. The morphological and structural features of nanoparticles were evaluated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy (FE-SEM) equipped by EDS analysis, Mössbauer spectroscopy and vibrating sample magnetometer. It was found that almost narrow size distribution of nanoparticles with cation distribution occupancy preference in octahedral site was synthesized. The nanoparticles were used for addition in subsequent solution for fabricating ferrite thin films with similar mentioned chemical composition. Several techniques including FE-SEM, atomic force microscopy and vibrating sample magnetometer were employed to find the role of strontium cation distribution on the structural and magnetic properties of films. The Curie temperature, coercivity and magnetic interaction which was evaluated by Henkel plot were reduced by an increase in substitution contents. Coercivity of thin films reduced from 0.65MA/m to 0.39MA/m and Curie temperature declined from 690 to 455°C. The value of strength of interaction was enhanced from −0.23 for x=0 to −0.75 for x=0.5. Angular dependence of coercivity proved that the magnetization reversal process was accompanied by the combination of domain wall motion and Stoner–Wohlfarth rotation, however for thin film with x=0.2–0.5, the reversal mechanism obey the Stoner–Wohlfarth rule.