Method for three-dimensional Ic(θ,φ,B,T) anisotropy characterization of REBCO tapes using advanced torque magnetometry; experimental results at principal field anisotropies up to 45 T

REBCO coated conductors (CCs) exhibit strong critical current anisotropy with respect to the magnetic field orientation relative to the tape plane, I c (θ, φ), which is crucial for high-field applications such as fusion magnets operating in complex field geometries. Quantitative characterization of this anisotropy using transport measurements becomes increasingly challenging at low temperatures, high magnetic fields, and high critical currents. In this work, we introduce a torque-magnetometry-based method that extends the capability of the standard two-dimensional (2D) torque measurements I c (θ) limited by fixed φ=0° to full three-dimensional (3D) characterization I c (θ, φ) with variable angle φ, as well as improves the accuracy of the evaluated critical currents. The study combines an analytical framework with redesigned torque probe components and is demonstrated experimentally up to 45 T. The effects of sample geometry, current redistribution, and intrinsic longitudinal–transverse anisotropy are quantified and incorporated into the analysis. The experimental part focuses on principal field anisotropies, i.e. I c (θ, 0°) and I c (θ, 90°), corresponding to maximum (MLF) and variable Lorentz force (VLF) configurations, respectively. It was observed that their ratio follows higher-order angular dependence and increases with the applied magnetic field. The presented method enables rapid, non-destructive 3D anisotropy characterisation I c (θ,φ,B,T) of the REBCO CCs in the temperature range 4.2 - 50 K and fields up to 45 T, extending anisotropy measurements into regimes difficult to access using conventional transport methods.