Enhanced tunability due to interfacial polarization in La0.7Sr0.3MnO3∕BaTiO3 multilayers

Ba Ti O 3 single layer and La0.7Sr0.3MnO3∕BaTiO3 multilayer films were fabricated by laser molecular-beam epitaxy. The voltage tunability of these films was investigated systematically in the frequency ranging from 10kHzto1MHz. The results suggest that the sizable tunability arises from the interfacial polarization which can be strongly suppressed by applied dc biases. In multilayer films, remarkable enhancement in voltage tunability was observed, because the interfacial polarization was greatly enhanced by an interfacial polarization associated possibly with the Maxwell-Wagner relaxation. The authors’ results indicate that the voltage tunability in low frequency (⩽1MHz) has a dominating contribution from the interfacial polarization.