Electrical property modulation of Au/Ba0.6Sr0.4TiO3/La0.7Sr0.3MnO3 structure by continuous composition spread Mn doping.

Composition spread Mn-doped Ba 0.6 Sr 0.4 Ti 1- x Mn x O 3 (BSTM x , 0 ≤ x ≤ 0.05) thin films were prepared on La 0.7 Sr 0.3 MnO 3 /SrTiO 3 (LSMO/STO) layer by combinatorial pulsed laser deposition. When x is less than 3.3%, the BSTM x films are single phase according to X-ray diffraction data, and the Au/BSTM x /LSMO structure presents asymmetric transport properties. The asymmetry of the transport property gets weak with increasing Mn doping concentration. The reverse-bias current density of the Au/BSTM x /LSMO structure remains at a low value of 10−7 A/cm2, and the forward-bias current density reduces rapidly with the ascending doping content (x ≤ 1.8%). Further increasing the Mn content, the differences between the positive and reverse current densities become smaller, and almost vanish when the Mn content is greater than 3.8%, indicating the disappearance of the asymmetry of the transport property. The effects of the LSMO electrode, Au/BSTM x Schottky junction, BSTM x thin film, and BSTM x /LSMO interface on the whole electrical transport properties are discussed by virtue of the experimental and fitted impedance spectrums. Our results are helpful for insight into the doping mechanisms in perovskite oxides. [ABSTRACT FROM AUTHOR]