SUPERCONDUCTIVITY UNDER PRESSURE IN BA1-XKXBIO3-Y

Measurements of the superconducting transition temperature T-c of Bi0. 62K0.38 BiO3-y with T-c = 27.5 K (sample 1) and Ba0.61K0.39Bi3-y with T-c = 17.6 K (sample 2) have been performed under a pressure up to 10 GPa by the inductive method. With increasing pressure, T-c of sample 1 initially increases, then has a maximum and finally decreases down to 6 K at 9.6 GPa. An irregularity in the dependence of T-c versus P is observed at about 8 GPa. For sample 2, T-c (P) demonstrates a qualitat ively similar behaviour with an additional dip in the low-pressure ran ge. The suppression of T-c is explained within the framework of the Bi lbro-McMillan model.