Study of impedance spectroscopy and electric modulus of PbTi1-xFexO3 (x=0.0-0.3) compounds

Single phase samples of PbTi1-xFexO3 (x = 0-0.3) were prepared and their structural and magnetic properties were studied followed by the detailed analysis of impedance spectroscopy and electric modulus data. Even though diamagnetic (x <= 0.05) and paramagnetic (0.1 <= x <= 0.2) behaviors are observed for the doping concentration upto 0.20, a ferromagnetic behavior is observed for x = 0.25 and 0.30 samples. The temperature variation of magnetization measurements and analysis for x = 0.25 and 0.30 samples show that these samples undergo ferromagnetic transition with transition temperature T-C around 650 K. The observed ferromagnetic behavior of these samples is explained in terms of double exchange interaction in Fe3+- O-2 - Fe(4+)networks. High temperature M e H loops were recorded and analyzed based on law of approach to saturation. The coercive field exhibits an anomalous behavior upto 500 K. The spectroscopic plots of Z'' and M'' reveal the presence of three electroactive regions such as grains, grain boundaries and surface layers and the analysis of Nyquist plots show the positive temperature coefficient behavior of resistance in these regions. (C) 2017 Elsevier B.V. All rights reserved.