High-pressure studies of superconductivity in $$\hbox {BiO}_{0.75}\hbox {F}_{0.25}\hbox {BiS}_{2}$$.

$$\hbox {BiO}_{0.75}\hbox {F}_{0.25}\hbox {BiS}_{2}$$ crystallizes in tetragonal CeOBiS $$_{2}$$ 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 $$\hbox {BiO}_{0.75}\hbox {F}_{0.25}\hbox {BiS}_{2}$$ . The $$T_{\mathrm{c}}$$ in our sample is 5.3 K, at ambient pressure, which is marginal but definite enhancement over $$T_{\mathrm{c}}$$ reported earlier (= 5.1 K). The upper critical field $$H_{\mathrm{c}2}$$ (0) is greater than 3 T, which is higher than earlier report on this material. As determined from the M- H curve, both $$H_{\mathrm{c}2}$$ and $$H_{\mathrm{c}1}$$ decrease under external pressure P (0 $$\le P \le $$ 1 GPa). We observe a decrease in critical current density and transition temperature on applying pressure in $$\hbox {BiO}_{0.75}\hbox {F}_{0.25}\hbox {BiS}_{2}$$ . [ABSTRACT FROM AUTHOR]