Abstract
Nano-particles of Ni0.5Mg0.5Fe2-xCrxO4 (0 <= x <= 1.0) have been synthesized by citrate-gel auto combustion method. X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to study the structural changes taking place with varying Cr concentration. Morphological analysis was made by scanning electron microscopy. The dielectric and magnetic properties were investigated by ac impedance spectroscopy and vibrating sample magnetometer (VSM), respectively. X-ray diffraction analysis assured the formation of single phase cubic spinel structure. Infrared spectroscopic studies revealed two main absorption bands in the range 400-800 cm(-1) arising due to tetrahedral (A) and octahedral (B) site vibrations. The dielectric properties have been carried out as a function of frequency (42 Hz-5 MHz) at room temperature. The dielectric behavior is explained on the basis of interface polarization, arising from the heterogeneous nature of ferrites structure. In general, substitution of chromium ion plays an important role tailoring the structural, dielectric and magnetic properties of the ferrite material.