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

A series of nickel-cadmium ferrite, Ni(0.9)Cd(0.1)GdxFe(2-x)O(4) (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.