Frequency-dependent dielectric permittivity and electric modulus studies and an empirical scaling in (100−x)BaTiO3/(x)La0.7Ca0.3MnO3 composites

Abstract

We have studied the dielectric permittivity and electrical modulus behavior in (100−x)BaTiO3/(x)La0.7Ca0.3MnO3 (x = 20, 30, 40, 50, 60 %) composites over a frequency range from 42 Hz to 5 MHz at room temperature. The dielectric permittivity data have been well interpreted using the Curie–Von Schweidler function adding the conduction contribution. The electric modulus data have been analyzed by invoking the decay relaxation function. Both formalisms describing a non-Debye type relaxation have been obtained in the composites. The electric modulus formalism indicates the Maxwell–Wagner–Sillars relaxation involved in the composite. In the scaled coordinate, the dielectric permittivity and electrical modulus for different x fall on a single master curve, indicating the existence of a general scaling formalism. The empirical scaling also signifies that the relaxation mechanism is independent of composition. In addition, we have proposed an Arrhenius-like equation for x-dependent dc conductivity and characteristic peak frequency in this composite system.