Rectifying properties and colossal magnetoresistance in La_(0.9)Hf_(0.1)MnO_3/Nb-0.7 wt-doped SrTiO_3 heterojunction

摘要

A heterojunction with good rectifying properties in a wide temperature range from 20 K to 300 K was fabricated simply by depositing an as-grown La_(0.9)Hf_(0.1)MnO_3 (LHMO) film on a commercial 0.7 wt% Nb-doped SrTiO_3 single crystal substrate using pulsed laser deposition technique. The current-voltage behavior of the LHMO/STON is measured under applied magnetic fields varying between 0 and 5 T. The heterojunction shows a remarkable magnetoresistance which depends on both the temperature and bias voltages. The sign of the magnetoresistance as function of temperature at either forward or reverse bias voltage is extensively studied by the filling of electrons in the e_g and t_(2g) band. The good rectifying behaviors, the magnetic tunable properties and the maximum magnetoresistance obtained at room temperature make this simple heterojunction promising for practical applications.