Two-axis Magnetic Field Orientation Dependence of Critical Current in Full-Width REBCO Coated Conductors

Abstract

Abstract Considerable progress has been made with the development of YBa2Cu3O7-δ and related rare-earth (REBCO) coated conductors in recent years. The introduction of BaZrO3 (BZO) nanoparticles has resulted in enhanced critical current density ( Jc ) for magnetic field orientations away from the intrinsic ab peak, with the absolute Jc and the degree of anisotropy depending on the geometry and orientation distribution of the nanoparticles; and REBCO coated conductors with a variety of substitutions and additions (Gd, Sm, Ba, Zr, Sn) are becoming commercially available in kilometre lengths. It is therefore increasingly important to characterise the magnetic field orientation dependence of critical current ( Ic ) in full-width coated conductors without destructive sample preparation, both for fundamental pinning studies and the design of large-scale applications. A two-axis goniometer has been developed, allowing the critical current to be measured as a function of both the magnitude and orientation of the applied magnetic field, Ic(B,θ,ϕ) , on full-width samples. Measurements of Ic(B,θ,ϕ) at 77 K are reported for four REBCO tapes made by metal organic chemical vapour deposition (MOCVD) with different rare earth content and the results interpreted in relation to rare earth substitution and pinning centre populations. The implications of the field orientation dependence for low and intermediate field applications are discussed.