50 MeV Li3+ ion irradiation induced modifications in dielectric properties of Al3+ substituted Mg-Mn ferrite

The 50 Mev Li3+ ion irradiation induced modifications on structural and electrical behaviors of Mg0.9Mn0.1AlxFe2-xO4 ferrites have been studied. A compressive strain is generated by the ion irradiation, observed by the X-ray diffraction studies, which have modified the electrical properties of these materials. The dispersion of dielectric constant epsilon in Mg0.9Mn0.1AlxFe2-xO4 ferrites of unirradiated samples is attributed to Maxwell-Wagner type interfacial polarization and Koop's theory. The dielectric constant of irradiated samples is decreased in magnitude from that of the unirradiated samples. This is explained on the basis of space charge polarization and the collective contributions of p- and n-type carriers. The electric loss parameter for irradiated sample shows the resonance peak, which can also be explained using Maxwell-Wagner interfacial polarization (matching of hopping frequency with frequency of an applied electric field). The resonance peaks in the unirradiated samples could not be observed as they probably lie beyond the measurable frequency range used in this work. (C) 2003 Elsevier Science B.V. All rights reserved.