Rectifying characteristics, magnetic tunability, and photovoltaic response in La0.8Hf0.2MnO3/0.7 wt% Nb-SrTiO3 heteroepitaxial junctions

Abstract

Heterojunctions composed of tetravalent cation-doped La 0.8Hf 0.2MnO 3 (LHMO) and 0.7 wt Nb-doped SrTiO 3 were fabricated using pulsed laser deposition method and investigated under different fields (electric, magnetic, and optic). The heterojunctions exhibited excellent rectifying behavior in a wide temperature range and significant magnetic field modulated properties. Prominent photovoltaic effect was also observed in the formed junctions. Special attention has been paid to the temperature dependence of the diffusion voltage (V d) and photovoltage (V oc). When temperature increased from 40 K to 300 K, V d decreased from 1.13 V to 0.16 V. It is notable that, under illumination of a light with λ = 532 nm, V oc dropped from 650 to 80 mV. No sudden change of V d and V oc was observed at the metal-insulator transition temperature, which is probably caused by the band structure of the LHMO. © 2012 American Institute of Physics.