Poster: Control Oxygen Vacancy and Carrier Concentration in Manganite/Chromate Heterostructures by Ionic Liquid Gating

Ultra thin films of crystalline oxide material exhibit a wide range of functional properties including tunable magnetism, superconductivity and metal-insulator transitions. These properties are strongly dependent on the strain, stoichiometry and crystal structure of the films. In this work, we investigate the effect of ionic liquid gating (ILG) on the structural, magnetic and transport properties of ultrathin manganite (LaSrMnO₃) and chromate (LaSrCrO₃) films grown on single crystal LaAlO₃ and SrTiO₃ substrates by molecular beam epitaxy. The effects of the ILG bias is studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transport measurements. For compressively-strained LaSrMnO₃ films, the application of a positive gate bias leads to an increase in the film resistivity and the creation of oxygen vacancies as evidenced by XPS and XRD measurements. Additionally, we find a reversible modulation of the transport and magnetic properties of LaSrMnO₃/LaSrCrO₃ heterostructures related to both the modulation of oxygen vacancies and the carrier concentrations. The results highlight the competing roles of charge and structural degrees of freedom in tuning the properties of nanoscale oxide materials.