The pnictide oxide superconductor was synthesized by a two-step solid reaction method. Gd–Fe–P ternary alloy was firstly prepared using pre-melting technology. The superconductivity at around 6.1K in GdFePO was observed. An annealing treatment done after synthesis could effectively reduce the dislocation density and furthermore affected the superconducting transition. Detail evidences based on transmission electron microscopy analysis revealed the relationship between the adjustable superconducting properties and the dislocations along [001] orientation of GdFePO.

Synthesis and Dislocations of 1111-type GdFePO Superconductor. C.Y.Liang, R.C.Che, F.Xia, X.L.Zhang, H.Cao, Q.S.Wu: Journal of Alloys and Compounds, 2010, 507[1], 93-6