Abstract
The temperature dependencies of the current-voltage (I-V) characteristics for the La2-xSrxCuO4 (LSCO) (x=0.10, 0.16, and 0.20)/1.0 wt % Nb-doped SrTiO3 (SNTO) heterojunctions were investigated under magnetic fields up to 14 T. The junction resistances for different heterojunctions show remarkable jumps as soon as the superconductivities of LSCO films occur. The diffusion voltages V-d and the fitting parameters E-00 in the field emission/thermionic-field emission formula, as well as the in-plane resistivities of LSCO films have the similar temperature and magnetic field dependencies. It is believed that both of the superconductivities of LSCO films and the inhomogeneous Schottky interfaces between LSCO and SNTO are responsible for the I-V characteristics of the heterojunctions. (C) 2010 American Institute of Physics. [doi:10.1063/1.3331964]