Magnetic properties of NiCuZn ferrites synthesized by oxalate precursor method

Ni–Cu–Zn ferrites have been synthesized by employing co-precipitation technique using oxalate precursors. X-ray diffractograms did not show impurity phases, indicating single-phase formation of the ferrites. The diffractograms of oxalate complex decomposed at 650 °C show that ferritization is complete up to 650 °C. Lattice parameter a (Å) was found to decrease with the addition of Ni2+ which is attributed to ionic sizes of Ni2+ (0.69 Å), which replaces Cu2+ (0.72 Å). From the thermogravimetric studies it is observed that the experimentally observed total mass loss (%), agrees with theoretically calculated mass loss (%) indicating maintenance of requisite stoichiometry. Initial permeability (μi ) shows increase when Ni2+ is added up to x=0.15x=0.15 while for (x>0.15x>0.15), it decreases. The increase in initial permeability (μi) is attributed to monotonic increase in Ms, and K1 on addition of Ni2+. However, the microstructure and density (porosity) also influence μi variations. The decrease in μi is attributable to increase of K1. The composition with density 91.14% exhibits large μi which also tends to increase with temperature up to 60 °C. Thus its usable range extends up to 60 °C. This samples has Tc near to 160 °C.