TUNABLE PHASE TRANSITION AND PHOTO-INDUCED RESISTANCE IN La0.8Ca0.2MnO3/FERROELECTRIC HETEROSTRUCTURES

Abstract

Heterostructures of La 0.8 Ca 0.2 MnO 3 (LCMO)/ferroelectric were formed by growing a layer of perovskite manganite LCMO on the ferroelectric 0.67 Pb ( Mg 1/3 Nb 2/3) O 3-0.33 PbTiO 3 (PMN-PT) single crystals. Well tunable structural, magnetic, and transport properties were achieved by applying electric fields on the formed heterostructures. By varying electric fields biased on the PMN-PT, the metal–insulator transition and resistance could be modulated continuously and reversely. Field modulation of photo-induced resistance (PR) was also observed. In situ X-ray diffraction indicates that the variation of resistance and PR result from the induced strain due to the coaction ferroelectric polarization or converse piezoelectric effect. The variations of PR under different fields differ significantly when PMN-PT was in positively and negatively polarized states. Such observations could be explained based on the coaction of piezoelectric effect and ferroelectric-field polarization, which subsequently affect the lattice strain and density of charge carrier in the grown LCMO layer.