HIGH PRESSURE STUDIES OF SUPERCONDUCTING Ba1−xKxBiO3

Abstract

We have studied the pressure effects of superconducting Ba 1−x K x BiO 3 for x=0.25, 0.30, 0.35 and 0.40 up to ~16 kbar . The superconducting transition temperature, Tc, increases linearly with pressure, P. We have found that dTc/dP decreases with increasing Tc, and reaches ~0 around Tc~29 K. For the x=0.35 sample, resistance reappears below Tc for pressure >12 kbar. This resistance depends strongly on the applied current. It becomes greater than the normal state resistance and noisy at high current.