Stress and field dependence of critical current in Ba2YCu3O7−δ superconductors

Abstract

Superconductors in practical applications are subjected to large stresses such as caused by coil winding, thermal contraction, and the Lorentz force generated by magnetic field. In this letter, the stress and field dependence of the critical current density ( J_C) of the high‐temperature superconductor (Ba₂YCu₃O_7−δ) has been investigated. It has been found that the J_C value is essentially independent of the applied stress, tensile or compressive, up to the level of fracture stress. This observation suggests that the grain boundary stress concentration is not likely to be one of the major causes of the ‘‘weak links’’ responsible for the relatively poor J_C values in polycrystalline Ba₂YCu₃O_7−δ. The rapid deterioration of J_C in applied magnetic field does not seem to be affected by the co‐presence of applied stress.