Characterization and Magnetic Properties of Nano-ferrite ZnFe2-xLaxO4 prepared by Co-precipitation method

Nano size spinel ferrite with nominal compositions ZnFe$_{2-x}$La$_{x}$O$_{4}$, 0.0$\leq{}$ x$\leq{}$ 0.3 were prepared using stoichiometric amounts of ZnCl$_{2}$, FeCl$_{3}$.6H$_{2}$O and LaCl$_{3}$.7H$_{2}$O by Co-precipitation method. The structures, optical and magnetic properties of the prepared samples were investigated, and compared with similar compositions prepared by different methods. The X-ray powder diffraction analysis shows single-phase cubic spinal structure up to x = 0.2. The lattice parameter ``\textit{a''} significantly increases with increasing x, which confirms the substitution of La at Fe sites. The crystallite size, estimated by different methods, has been found in the range of 7-14 nm. This crystallite size is found to be less than that prepared by sol gel combustion method. The FTIR spectra indicate the presence of absorption bands in the range of 390- 561cm$^{-1}$. The magnetic hysteresis was studied using vibrating sample magnetometer (VSM). The saturation magnetization, coericivity and remnants magnetization have nonsystematic change as the La-substitution increases. This is because the magnetic properties of Nano- ferrites are strongly dependent on the cation distribution among tetrahedral and octahedral sites in the cubic spinel structure.