AC conductivity and magnetoelectric effect in MnFe1.8Cr0.2O4-BaTiO3 composites

Magnetoelectric composites with composition xBaTiO(3) + (1 - x)MnFe1.8Cr0.2O4 in which x varies as 1, 0.85, 0.7, 0.55 and 0 were prepared by a standard ceramic technique. X-Ray analysis confirms single-phase formation in x = 1 and x = 0 compositions whereas the presence of both phases in x = 0.85, 0.7 and 0.55 compositions. The dielectric constant (epsilon '), loss tangent (tan delta) and AC conductivity (sigma (AC)) of the composites have been investigated in the frequency range 100 Hz-1 MHz and also in the temperature range 30-400 degreesC. The results obtained are interpreted in terms of a polaron hopping mechanism. Static magnetoelectric conversion factor (dE/dH) as a function of magnetic field was measured in x = 0.85, 0.70 and 0.55 compositions. The maximum value of dE/dH obtained was 150 muV/(cm(-1) x Oe) for x = 0.85 composition. (C) 2001 Published by Elsevier Science B.V.