Transport and magnetic properties of yttrium doped NdFeAs(O,F) superconductor

The transport and magnetic properties of the undoped and yttrium doped NdFeAs(O,F) superconductor are investigated in detail for the first time. The transition temperatures of the yttrium doped samples are found to increase monotonically and attain a maximum of 53.3 K for 30% yttrium doping, ∼4 K higher as compared to the yttrium free sample. The TC values observed from the temperature dependent ac susceptibility measurements are also in agreement with the resistivity measurements. Yttrium doping is found to decrease the lattice parameters of the system; causing an inner chemical pressure and thereby accomplishing a TC enhancement. Moreover, the substitution of relatively smaller yttrium ion at Nd site creates lattice defects which act as effective pinning centers thereby enhancing the JC(H) performance of the system.

► The superconducting properties of Y doped Nd1111 is studied for the first time.
► Y doping increases the TC up to 4 K with a maximum TC of 53.3 K with 30% Y doping.
► The creation of lattice defects by Y doping enhances FP(H) and thereby the JC(H).