Abstract

Acoustoelectric Nonlinearity in Manganite Films

K.Dyakonov, A.Goltsev, L.A.Kulakova, E.Yakhkind (Ioffe Physico-Technical Institute RAS, St.Petersburg, Russia); V.P.Dyakonov, A.Klimov, S.J.Lewandowski, H.Szymczak (Institute of Physics, Warszawa, Poland)

e-mail: L.Kulakova@pop.ioffe.rssi.ru; Yakhkind@pop.ioffe.rssi.ru

Interplay between the double exchange and strong electron-phonon interaction is responsible for unusual magnetic and transport properties of manganites. In this report we present results of acoustoelectric (AE) effect study in La0.67Ca0.33MnO3 (LCMO) films over a wide temperature range encompassing the metal-insulator (M-I) transition region. The experiments on the AE effect in the LCMO films unexpectedly revealed an anomalous contribution to the AE current, invariant upon reversal of the SAW propagation, which coexists with the ordinary (odd in the SAW wave vector) effect. The anomalous effect dominates near the M-I transition, while the ordinary effect prevails at high and low temperatures and its sign corresponds to the hole-like conductivity in the whole temperature range. Due to complex of experiments and their theoretical treatment we have shown that the anomalous AE effect is caused by the strong modulation of the film conductivity produced by the SAW elastic deformations

Section : 2