Gamma irradiation induced structural, electrical, magnetic and ferroelectric transformation in bismuth doped nanosized cobalt ferrite for various applications

The effects of gamma irradiation on the structural, dielectric, magnetic and ferroelectric behaviour of Bi doped cobalt ferrite, CoFe2-xBixO4 (x = 0, 0.05, 0.1, 0.5, 1.0) synthesized by glycine nitrate method before and after gamma irradiation have been investigated. A micro-strain is generated by the gamma irradiation as observed by the X-ray diffraction studies. The massive enhancement of dielectric constant in irradiated samples is attributed to the Maxwell-Wagner type of interfacial polarization. Complex impedance analysis indicates a predominant grain boundary contribution to the conduction mechanism. The frequency-dependent ac conductivity in the frequency range of 100 Hz - 1 MHz is increased on irradiation. Reduction in magnetisation was found in the irradiated samples. Remnant polarization and coercive field decreases with irradiation as obtained from P-E loop. Hence, the applications of these nanoferrites in the field of high frequency and magnetic recording devices can be favoured by tailoring the electrical and magnetic properties subjected to gamma irradiation.