Structure and Magnetic Properties of NiZnCo Ferrites with Different Gd Dopings

The rare earth doped nickel zinc cobalt ferrites were prepared by the sol-gel self combustion method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM) were used to characterize the nickel zinc cobalt ferrite to explore the impact of Gd doping on microstructure and magnetic properties of NiZnCo ferrite. The results showed that with the increase of rare earth doping amount, the lattice parameters of NiZnCo ferrite increased firstly and then decreased, the grain size and the stress increased, and the second phase appeared when the doping amount was 0.1. The particles of Gd doped samples were rounder and more uniform in size. The cations were redistributed in the crystal lattice, when the doping amount of Gd was less than 0.04, some Gd ions entered the A position and also some Zn ions were extruded to the B position. When the doping amount of Gd exceeded 0.04, the Gd ions which occupied the A position decreased until all Gd ions occupied the B position, while Zn ions returned back to the A position. The saturation magnetization decreased monotonously from 108 to 43 mA•m2•g-1, with the increase of Gd doping. And the coercivity increased slightly when the amount of Gd doping was 0.02, and then decreased monotonically. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.