No abstract

Nickel cobalt ferrite, Ni 0.5 Co 0.5 Fe 2 O 4 , has been prepared by precursor combustion technique from hexahydrazine nickel cobalt ferrous succinate precursor. The precursor was characterized by chemical analysis, CHNS analysis, infrared spectroscopy, TG-DTA and mass loss studies. The thermal data show how the precursor decomposes in four steps to give stable ferrite phase. The precursor decomposes autocatalytically once initially ignited, to give the 'as-prepared' nano-spinel ferrite. The X-ray diffraction analysis reveals single cubic spinel phase structure. The infrared measurements between 4000 and 350 cm -1 confirmed the intrinsic cation vibrations of the spinel structure. The SEM image clearly shows the nanosized nature of the ferrite. The dielectric constant and loss tangent are found to decrease with increase in frequency which is due to Maxwell-Wagner interfacial polarization. The loss tangent shows a relaxation peak at *1 kHz. The variation of DC electrical resistivity with temperature indicates semiconductor behaviour. The temperature-and field-dependent magnetization data of 'as-prepared' ferrite reveal that the lattice has either a canted or partially misaligned spin structure due to the nanosized nature of the ferrite.