Determination of the strain dependence of resistance in La[sub 0.7]Sr[sub 0.3]MnO₃/PMN-PT using the converse piezoelectric effect

Abstract

We have deposited La[sub 0.7]Sr[sub 0.3]MnO₃ (LSMO) thin films on piezoelectric (1−x)Pb(Mg[sub ⅓]Nb[sub ⅔])O₃−xPbTiO₃ (x~0.3)(PMN-PT) single-crystal substrates and studied the effects of substrate-induced lattice strain on the resistance of the LSMO films. By applying electric fields across the PMN-PT substrate, we in situ induce an in-plane compressive (tensile) strain in the PMN-PT substrate via the converse piezoelectric effect. The induced strain is transferred to the LSMO film, which then imposes an in-plane compressive (tensile) strain on the LSMO film, thereby causing a linear decrease (increase) in the resistance of the LSMO film. Based on the experimental results, we establish quantitative relationships between the resistance of the LSMO film and the converse piezoelectric-effect-induced out-of-plane and in-plane strains in the PMN-PT substrate and LSMO film, respectively.