Effect of Gd³⁺doping on the structural and magnetic properties of nanocrystalline Ni–Cd mixed ferrite

Abstract

A series of nickel–cadmium ferrite, Ni0.9Cd0.1GdxFe2−xO4 (x=0, 0.1, 0.2 and 0.3), was prepared through the sol–gel technique. Samples were characterized using x-ray diffraction (XRD), Fourier transform infrared spectroscopy, a wavelength dispersive x-ray fluorescence spectrometer, a transmission electron microscope and a vibrating sample magnetometer. XRD analysis confirmed the formation of single-phase spinel structure in all the samples. The effect of Gd3+ doping on the crystalline phase, crystallite size and magnetic properties was investigated in detail. Gadolinium doping improved the crystallinity and induced compressive strain in Ni–Cd mixed ferrite. The lattice parameter was observed to increase for minor Gd3+ doping (up to x=0.1); however, further doping resulted in a reduction of the lattice constant. The saturation magnetization decreased and coercivity increased with an increase in gadolinium content.