Low-Temperature Scaling of the Critical Current in 1 G HTS Wires

We present highly detailed temperature, magnetic field and field angle dependent measurements of the critical current of a state-of-the-art commercial first-generation Bi-2223 high temperature superconductor wire (Sumitomo new type H high current density DI-BSCCO). By scaling the applied field values at different angles using the Blatter electron mass anisotropy expression, we demonstrate that the measurements at each temperature from 20 to 85 K collapse onto a common curve with respect to the scaled magnetic field. However, the scaling parameter is found to range from 7 at 80 K to 13 at 25 K, far below the values reported in the literature for the electron mass anisotropy of this material, and far closer to the values reported for similar analyses of data obtained from the much less anisotropic superconductor YBCO. This suggests that a mechanism of similar magnitude underlies and determines the results obtained for both materials in spite of their greatly differing electronic mass anisotropies. By normalizing the results to the self-field critical current and the irreversibility field, we are able to obtain a single universal curve describing the performance of the superconductor across the full range of operating conditions. In contrast to pinning-engineered YBCO coated conductors, we find that the low-temperature behavior of BSCCO wires can be well correlated with its high-temperature behavior. Knowledge of this straightforward behavior of this commercial superconductor across the full parameter space of temperature, field and field angle will be invaluable to engineers working with this material to construct machines or devices.