Study of Cu, Co, Mn and La doped NiZn ferrite nanorods synthesized by the coprecipitation method

Abstract

The Zn- and Ni-doped spicular α-FeOOH precursor sample was obtained by coprecipitation-air oxidation method. The Ni 0.5Zn 0.5Fe 2O 4 nanorods with an average diameter of 40 nm and an aspect ratio of 20 were prepared after the calcination process for maintaining the morphology of α-FeOOH precursor. Cu, Co, Mn and La were doped into Ni 0.5Zn 0.5Fe 2O 4 to prepare Ni 0.4M 0.1Zn 0.5Fe 2O 4 (M represents Cu, Co, Mn, La) nanorods. The phase, morphology and particle diameter of the samples were studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the aspect ratio of the Ni 0.4M 0.1Zn 0.5Fe 2O 4 decreased with an increase in the absolute difference of the radius of the dopant ion and Fe 2+. Therefore, the aspect ratio of the Ni 0.4Cu 0.1Zn 0.5Fe 2O 4 nanorods obtained by doping Cu was maximal and the value was higher than 25. The magnetic properties were measured using a vibrating sample magnetometer (VSM), which indicated that the coercivity of the Ni 0.4M 0.1Zn 0.5Fe 2O 4 sample decreased and the magnetization increased with an increase in the calcination temperature. The higher anisotropy due to the rod-like structure of the ferrites is responsible for the superior magnetic properties obtained in the present work compared to those reported for ferrites with irregular grain shapes.