Impedance and magnetoelectric characteristics of (1 - x)BaTiO₃-xLa_0.7Sr_0.3MnO₃ (x = 0.1 and 0.3) nano-composites

We have synthesized the phase-pure (1 - x)BaTiO₃-xLa_0.7Sr_0.3MnO₃ (x = 0.1 and 0.3) magnetoelectric composites without interdiffusion among the existing phases. The magnetic measurements revealed an anomaly at the ferroelectric Curie temperature (393 K) of BaTiO₃, and the dielectric data revealed an anomaly at the ferromagnetic transition temperature (360 K) of La_0.7Sr_0.3MnO₃ ascertaining the magnetoelectric coupling in the composite. Impedance analysis indicated dipolar polarization contributions to the dielectric spectrum with two non-Debye-type relaxations. Both the grain and grain boundary contributions were present in the system with dominant grain boundary effect in all the composites. The composites show semiconducting behavior with the barrier hopping-type conducting mechanism. To avoid the free charge carrier and the space charge contributions, the magnetoelectric response was measured at high frequency range. The maximum values of magnetoelectric voltage coefficient measured at 100 kHz were 221 and 219 mV/Oe-cm for x = 0.1 and 0.3 samples, respectively. (orig.)