Investigation of magnetic behaviour of Ni-Fe-O prepared by the solid state method

Polycrystalline Fe doped NiO was prepared by the solid state method with the aim of exploring its suitability as a functional material for spintronics applications. Phase pure samples (up to 2% doping of Fe) as evident from x-ray diffraction were characterized to investigate the magnetic, electric and dielectric properties. Magnetic measurements using the vibrating sample magnetometer clearly reveal ferromagnetic behaviour at room temperature. The activation energies of the doped samples, determined from impedance spectroscopy, were found to be relatively higher than that of undoped NiO. It is also observed that Fe doping has no significant effect on the dielectric properties of the samples. Thermogravimetric analysis, carried out to find the Curie temperature (T-C), leads to a remarkable insight into the observed ferromagnetism by identifying the presence of secondary phase NiFe2O4.