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

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. (orig.)