Pt/(Ba0.7Sr0.3)TiO3(BST)/YBa2Cu3O7-x(YBCO) capacitors were fabricated on (001) LaAlO3 substrates. The leakage current density-electric field characteristics were measured in the temperature range from 20 to 300 K. In the electric field region of >0.7 MV/cm for positively biased Pt electrode and >1.4 MV/cm for negatively biased Pt electrode, the leakage current shows space-charge-limited-current behavior from 20 to 250 K. Meanwhile a positive temperature coefficient of resistivity (PTCR) in the temperature range from 20 to 150 K was observed and attributed to the strong negative temperature dependence of the dielectric constant of BST thin films. (C) 2004 American Institute of Physics.