Study of structural, morphological and electrical properties of Ce doped NiFe_2O_4 nanoparticles and their electronic structure investigation

摘要

Present work reports the structural, morphological, electrical properties of the Ce doped nickel ferrite (NiFe_2O_4) compounds and their electronic structures studied by X-ray absorption spectroscopy. The samples of NiFe_(2-x)Ce_xO_4 (x = 0.0-0.10) were prepared by the chemical route and sintered at 1100 °C for 3 h. X-ray diffraction patterns of these sintered pellets show that Ce doped samples exhibit pure spinel phase up to x = 0.03. With increase of Ce concentration the crystallite size of the samples change randomly, however lattice parameters do not exhibit any significant change. Temperature dependent resistivity shows semiconducting nature for all the compositions. Sample with Ce concentration x = 0.04 shows maximum resistivity. The sample with x = 0.02 shows highest dielectric constant in the frequency range of 75 kHz-1 MHz at room temperature. The observed results are discussed on the basis of change in the electronic structure of these compounds with the Ce concentration. It has been observed that valence state of Ce ion is playing dominant role in determining the electrical and dielectric properties of the synthesized system.