Superconducting and critical properties ofPrOFe0.9Co0.1As: effect of P doping

Abstract

PrOFe0.9Co0.1As is known to be asuperconductor with a TC of ∼ 14 K. In an attempt to induce charge transfer and also induce chemical pressure between theFeAs and PrO layers we have synthesized for the first time oxypnictides of the typePrOFe0.9Co0.1As1 − xPx (Pdoping at As sites). All the compounds crystallize in the tetragonal ZrCuSiAs-type structure (spacegroup = P4/nmm). The latticeparameters (a and c) decrease as expected on substitution of smaller phosphorus at the arsenic site inPrOFe0.9Co0.1As and adecrease in TC was observed on substitution of P ions at a low rate of0.13 K/at.% of P forx > 0.1. The irreversibilityfield (Hirr) and criticalcurrent density (JC), obtained using the AC susceptibility measurements, werefound to decrease monotonically with increasing P concentration.Hirr is observed to bemuch smaller than HC2, pointing to a very low pinning energy. The pinning potential obtained using bothin-field transport and AC susceptibility measurements indicates a low value of ∼ 40 meV and shows no significant variation with P substitution.