Improvement of the pinning property in YBa2Cu3O7−  x  films below 35 K by doping with graphene oxide

Jun Wang,Qiangqiang Zhang,Xingyi Zhang,Cong Liu

doi:10.1063/1.5063485

Abstract

Pinning induction in REBa2Cu3O7−x (RE = rare earth) films and coated conductors improves their critical current density (Jc). In general, however, interstitial elements, e.g., C and N, cannot act as effective pinning centers in REBa2Cu3O7−x materials because they typically lead to degeneration of the superconducting properties. In this work, the influence of graphene oxide (GO) on YBa2Cu3O7−x (YBCO) films was studied by measuring the critical temperature and angle-dependent critical current density. The results revealed that the concentration of GO in YBCO films modulated the critical temperature. The decay rate of Jc in H∥c field orientations decreased with decreasing temperature. At 35 K and 4.2 K, the YBCO/GO film exhibited a lower decay of Jc and less anisotropic behavior than the YBCO-BaMO3 (M = Zr, Hf) film. GO doping could, therefore, improve the pinning property of YBCO films below 35 K. This improvement could be due to the presence of nanosized carbon structures, which served as isotropic pinning centers at low temperature, as revealed by high-resolution transmission electron microscopy.

Highlights

MacManus-Driscoll et al and Haugan et al first reported the use of BaZrO3 (BZO) and Y2BaCuO5 (Y211) nanoparticles to significantly improve the critical current density of YBa2Cu3O7−x (YBCO) films and coated conductors.1–3 Such nanoparticles serve as strong artificial pinning centers (APCs) and have attracted considerable attention in the construction of REBa2Cu3O7−x (RE = rare earth) films and coated conductors
We report the critical temperature, angledependent critical current density, and vortex pinning properties of graphene oxide (GO)-doped YBCO films on single-crystal substrates
The surface microstructures of YBCO (Figure 2(a)) and YBCO/1% GO (Figure 2(b)) clearly show that GO affected the mode of grain growth

Summary

INTRODUCTION

MacManus-Driscoll et al and Haugan et al first reported the use of BaZrO3 (BZO) and Y2BaCuO5 (Y211) nanoparticles to significantly improve the critical current density of YBa2Cu3O7−x (YBCO) films and coated conductors.. MacManus-Driscoll et al and Haugan et al first reported the use of BaZrO3 (BZO) and Y2BaCuO5 (Y211) nanoparticles to significantly improve the critical current density of YBa2Cu3O7−x (YBCO) films and coated conductors.1–3 Such nanoparticles serve as strong artificial pinning centers (APCs) and have attracted considerable attention in the construction of REBa2Cu3O7−x (RE = rare earth) films and coated conductors. The layered structure induces an intrinsic anisotropic behavior in thin YBCO structures, of which the mass anisotropic value is 5–7 For practical applications, such as coil tapes in superconducting magnets, isotropic current capacity is more favored, and anisotropy needs to be kept as low as possible.

EXPERIMENTAL

RESULTS AND DISCUSSION

Effect of GO on Tc

Dependence of Jc on the magnetic field at low temperatures

CONCLUSIONS