Study of ac impedance spectroscopy of Al doped MnFe2-2xAl2xO4

We have reported electrical properties of Al doped MnFe2O4 ferrite using ac impedance spectroscopy as a function of frequency (42 Hz to 5 MHz) at different temperatures (300-473 K). XRD analysis shows that all the compositions are single phase cubic spinel in structure. The complex impedance analysis has been used to separate the grain and grain boundary resistance of MnFe2-2xAl2xO4. From the analysis of impedance spectra it is found that the real (Z'), and imaginary (Z '') part of the impedance decrease with increasing frequency and both are found to decrease with Al doping up to 20%, and thereafter, these increase with further increasing the Al concentration. Experimental results have been fitted with two parallel RC equivalent circuits in series. (C) 2009 Elsevier B.V. All rights reserved.