科研之友
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摘要
A complex of studies of the physical properties of thin lanthanum manganite La0.67Ca0.33MnO3 films were performed for a monolithic layered structure consisting of a LiNbO3 substrate and a La0.67Ca0.33MnO3 thin epitaxial film. For the first time, not only ordinary acoustoelectric (AE) current of charge carriers dragged by a surface acoustic wave, but also longitudinal anomalous AE current, which flowed in a distinguished direction independent of the direction of the surface acoustic wave propagation, was observed. The anomalous AE effect predominated close to the metal-insulator transition, whereas the odd AE effect predominated at high and low temperatures. The sign of the ordinary odd AE effect corresponded to hole conduction of the film. A theoretical analysis showed that the anomalous AE effect is due to a strong film conduction modulation caused by deformation created by the surface acoustic wave. The theoretical results were in close agreement with experiment. The temperature dependences of resistivity rho (both in the absence of a magnetic field and in fields of up to 3 T), high-frequency magnetic susceptibility, and thermoelectric power were studied.
- 出版日期2002
