Diffuse Dielectric Anomalies in (x)•Bi0.95Mn0.05FeO3-(1-x)•Ni0.5Zn0.5Fe2O4 multiferroic composites

Multiferroic composites of x(center dot)Bi(0.95)Mn(0.05)FeO(3)-(1-x)(center dot)Ni0.5Zn0.5Fe2O4, where x takes the values of 0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1, have been prepared by combining sol-gel autocombustion and solid state methods. XRD and SEM-EDX measurements on the samples were used to evaluate the structural analysis. Dielectric properties of the composites have been studied as a function of frequency (1 Hz-1 MHz) and temperature (50-350 degrees C). Two diffuse dielectric anomalies were observed, one at around 100-150 degrees C and the other at around 260-340 degrees C, and they were attributed to structural inhomogeneities, Bi/O vacancies and dipole induced charge carrier hopping motions at low temperatures, and to magnetic phase transitions and magneto-electric coupling at high temperatures. Electrical conductivity studies on the samples reveal that the conduction processes are frequency dependent. The results are explained in terms of obtaining a correlation between the structure, chemical modifications and the possible interplay between the obtained parameters of the composites. (C) 2015 Elsevier B.V. All rights reserved.