A high-T c superconducting diode with large current carrying capacity

Abstract

Superconducting diodes enable lossless current flow in one direction and could serve in a variety of applications similar to their semiconductor counterparts, such as current rectification, temperature sensing, and logic circuits. However, no superconducting diodes reported in the literature have a forward current carrying capacity exceeding 1 A, and hence are not suitable for use in superconducting power applications. Here, we present a high-Tc superconducting diode that leverages permanent magnets to induce an asymmetry in the critical current of a superconducting coated conductor upon current reversal. The magnets are arranged to replicate the self-field of the conductor at Ic, causing constructive or destructive interference with the transport current's self-field depending on the current direction. This interference generates asymmetric internal magnetic field distributions, leading to the directional suppression of the critical current density and a diode effect. We demonstrate ΔIc values > 150 A and a half-wave transformer rectifier using a single high-Tc flux diode submerged in liquid nitrogen, which rectifies 30 A into a 220 μH superconducting magnet.