Near-isotropic performance of intrinsically anisotropic high-temperature superconducting tapes due to self-assembled nanostructures

TL;DR

This paper demonstrates that high-temperature superconductor tapes can exhibit nearly isotropic critical current performance across different magnetic field orientations due to self-assembled nanostructures that enhance flux pinning.

Contribution

It reveals a novel field and temperature-dependent phenomenon where HTS tapes show orientation-independent critical current, linked to nanoscale flux pinning structures.

Findings

Critical current becomes orientation-independent at specific fields and temperatures.

Strong flux pinning by nanoscale structures is key to isotropic performance.

A simple model explains the anisotropic electronic response and guides material tuning.

Abstract

High-temperature superconductors (HTS) are finding use as high - current wires for potential application in power devices. The dependence of their basal-plane critical current properties on orientation in a magnetic field can pose important design problems. Here we report material and operating parameter conditions where prototype HTS tape conductors exhibit critical current characteristics that are essentially field-orientation independent. The novel phenomenon is observed for specific magnetic field intensities that depend on the operating temperature, and in materials having strong flux pinning by extended nanoscale structures aligned roughly along the HTS crystalline c-axis. The effect can be described by a simple model for the field dependence of critical current density, generalized for anisotropic electronic response. This description may provide insight into means to fine-tune the material properties for nearly isotropic performance characteristics at a preferred field and temperature.