Reduced A–B super exchange interaction in zirconium doped cobalt ferrite due to laser irradiation

Abstract

The impact of Nd:YAG laser irradiation and the addition of zirconium ions (Zr4+) on the physical properties of CoFe2O4 spinel nano-ferrites has been studied. The co-precipitation method was used to synthesize the samples. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) were employed to examine the structure and morphology. The decrease in the Curie temperature Tc is due to the laser irradiation and the increase in the Zr content of the sample. This decline in Tc is a result of an increase in the canting of the spins, leading to a change in the thermal energy needed for compensate the spin alignment. The difference in the Tc between the non irradiated and the irradiated samples is about 7%, 43% and 34% for CoFe2O4, Co1.1Zr0.1Fe1.8O4, and Co1.3Zr0.3Fe1.4O4, respectively. The decrease in the coercivity of the laser irradiated sample is due to a reduction in the magnetic anisotropy and an altered distribution of the cations (Co2+, Fe3+, Zr4+). The observed trend indicates that laser irradiation, and Zr substitution, can be used to modify the magnetic hardness of the samples. The low coercivity of irradiated Co1.1Zr0.1Fe1.8O4 makes it suitable for a range of applications. The high-frequency response of the Co1+xZrxFe2–2xO4 NPs shows that they can operate within the frequency range of 7.5 GHz–11.56 GHz.