Effect of pressure on normal and superconducting state properties of iron based superconductor PrFeAsO(0.6)F(y) (y = 0.12, 0.14)

The effect of high pressure (up to 8 GPa) on normal and superconducting state properties of PrFeAsO(0.6)F(0.12), an 1111-type iron based superconductor close to optimal doped region, has been investigated by measuring the temperature dependence of resistivity. Initially, the superconducting transition temperature (T (c)) is observed to increase slowly by about 1 K as pressure (P) increases from 0 to 1.3 GPa. With further increase in pressure above 1.3 GPa, T (c) decreases at the rate of ~1.5 K/GPa. The normal-state resistivity decreases monotonically up to 8 GPa. We have also measured the pressure dependence of magnetization (M) on the same piece of PrFeAsO(0.6)F(0.12) sample up to 1.1 GPa and observed T (c) as well as the size of the Meissner signal to increase with pressure in this low-pressure region. In contrast, for an over-doped PrFeAsO(0.6)F(0.14) sample, magnetization measurements up to 1.06 GPa show that both T (c) and the Meissner signal decrease with pressure. The present study clearly reveals two distinct regions in the dome-shaped (T (c)-P) phase diagram of PrFeAsO(0.6)F(0.12).