Dielectric and Magnetic Properties of NiFe2-xBixO4 Nanoparticles at Microwave Frequencies Prepared via co-precipitation Method

NiFe 2-x Bi x O 4 (x = 0, 0.1, 0.15, 0.20 and 0.25) nanopowders were synthesized via chemical co-precipitation method. The precursor gels were sintered at 973 K in air for 2 h to obtain the single phase pure nanostructured NiFe 2-x Bi x O 4 spinel. The crystal structure and magnetic properties of the substituted spinel series of NiFe 2-x Bi x O 4 have been investigated by means x-ray diffraction and vibrating sample magnetometer. The values of the saturation magnetization and the coercive field of NiFe 2-x Bi x O 4 nanoparticles were found to decrease with increasing degree of bismuth substitution. The room temperature real and imaginary part of permittivity was measured from 1 MHz to 1.8 GHz. The real part of permittivity was found to increase with increase of bismuth content. The room temperature electron paramagnetic resonance was studied to investigate the magnetic properties at microwave frequency.