Graphene doping effects on the magnetic and transport properties of YBa2Cu3O7-δ high temperature superconductor

Abstract

In this work, bulk graphene-doped YBa2Cu3O7-δ (YBCO) high-temperature superconductor samples were prepared with composition of YBCO + x wt.% graphene nanoplatelets (G) (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0). The X-ray diffraction patterns show the YBCO orthorhombic phase in all the samples. The SEM images show good grain connectivity between YBCO grains in graphene-doped samples. Furthermore, the broadening of resistivity under applied magnetic fields up to 9T and thermally activated flux creep in the mixed state were studied using Arrhenius plots. The activation energy U0 (H) increased with graphene doping results in better flux pinning and higher critical current densities. Moreover, improvement in the critical temperature (TC), upper critical field (μ0HC2) and the irreversibility field (μ0Hirr) were observed in graphene-doped samples as compared to the pure YBCO sample.