High-pressure studies of superconductivity in BiO_0.75F_0.25BiS₂

BiO0.75F0.25BiS2 crystallizes in tetragonal CeOBiS2 structure (S. G. P4/nmm). We have investigated the effect of pressure on magnetization measurements. Our studies suggest improved superconducting properties in polycrystalline samples of BiO0.75F0.25BiS2. The T-c in our sample is 5.3 K, at ambient pressure, which is marginal but definite enhancement over T-c reported earlier (= 5.1 K). The upper critical field H-c2(0) is greater than 3 T, which is higher than earlier report on this material. As determined from the M-H curve, both H-c2 and H-c1 decrease under external pressure P (0 <= P <= 1 GPa). We observe a decrease in critical current density and transition temperature on applying pressure in BiO0.75F0.25BiS2