Investigation of effect of x in Yb1-xGdxBa 2Cu3O7-y superconducting structures on upper critical magnetic field and coherence length

Abstract

The resistivity measurements of the Yb1-xGdxBa 2Cu3O7-y superconducting samples prepared by using the solid-state reaction technique for x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 were performed in QD-PPMS system under different magnetic fields up to 5T in zero field cooling regime. The upper magnetic field Hc2(T=0) for each sample was calculated from 50% of the normalized resistivity (Rn) by the extrapolation Hc2(T) to T=0K and the coherence lengths ?(T=0) of the samples were calculated from the Hc2(0) values. The examination of the effects of x in the composition on Hc2(0) showed us that the upper critical magnetic field decreased from 186.31T for x=0.0 to 37.99T for x=1.0 with the increasing of content x from x=0.0 to 1.0. Using the content x in the composition, the upper critical magnetic field can be controlled and this can be used in superconducting application especially as a superconducting relays. © 2009 IOP Publishing Ltd.