Ionic Liquid Gating and Phase Transition Induced Semiconducting to Metallic Transition in La0.67Sr0.33MnO3/BaTiO3 Heterostructures.

The strongly correlated La0.67Sr0.33MnO3 (LSMO) thin films were deposited on the BaTiO3 (BTO) substrates to study the influence of temperature-dependent phase transition of BTO on the magnetic and electric transport properties of the LSMO films. Because of the large lattice mismatch between the LSMO and BTO substrates, the ultrathin LSMO film exhibits semiconducting transport behavior rather than the normal metal-insulator transition behavior. A Mn2+-O2--Mn3+ dominated double exchange interaction, which leads to a semiconducting to metallic transition behavior, was formed by the joint effect of the ion-liquid gating and phase transition of the BTO substrates. Our work shows a special way to modulate the conduction mechanism, which opens up a new field for further study of the magnetoelectric coupling of the LSMO/BTO heterostructures.