Critical Current Density of ${\rm YBa}_{2}{\rm Cu}_{3}{\rm O}_{7-\delta}$ Coated Conductors Under High Compression in High Fields

Abstract

From an engineering standpoint, the magnetic field (B), temperature (T), and strain dependence (e) of the critical current density (JC) in practical superconducting wires/tapes is critical for optimizing device design using superconducting technology. The highly anisotropic and brittle nature of YBa2Cu3O7-δ (YBCO) coated conductor tapes means a detailed investigation of the parameters that affect the critical current is a challenging experimental task to achieve within a single strain apparatus. Here we present critical current measurements as a function of strain on YBCO coated conductors made using a bending apparatus designed for use in horizontal split-pair magnet systems with a 40 mm diameter bore. The design and configuration of the apparatus allows different compressive and tensile strain between -1.4% <; eapplied <; +0.5% to be applied. Magnetic fields up to 0.7 T at T=77 K , and 15 T at 4.2 K, were applied at different angles (θ) with respect to the coated conductor surface. At 77 K, JC can be reversibly reduced by more than 85% with a ~ -1% compressive strain at 0.7 T. For high compressive strains, JC versus strain data show convex behavior. We provide a preliminary parameterization of the scaling relation for JC (B,T,e,θ).