Nonvolatile Magneto-Thermal Switching in MgB2

TL;DR

This study demonstrates nonvolatile magneto-thermal switching in MgB2, a superconductor capable of trapping magnetic flux, which could enable advanced thermal control applications.

Contribution

It reveals nonvolatile MTS in MgB2 due to flux trapping, expanding understanding of superconducting materials for thermal switching.

Findings

Magnetic flux is trapped in MgB2 after demagnetization.

Nonvolatile MTS observed in MgB2 and Sn-Pb solders.

Flux trapping may be common in superconductors with thermal switching capabilities.

Abstract

Ongoing research explores thermal switching materials to control heat flow. Specifically, there has been interest in magneto-thermal switching (MTS) materials based on superconductors, which only exhibited switching behavior when a magnetic field was applied. However, a recent report highlighted nonvolatile MTS in commercial Sn-Pb solders, attributed to magnetic flux trapping. In this study, we focused on flux trapping in a type-II superconductor MgB2. Magnetization and thermal conductivity measurements under magnetic fields were conducted on polycrystalline MgB2. We confirmed that magnetic flux was indeed trapped in MgB2 even after demagnetization. Additionally, we observed nonvolatile MTS in MgB2 as well as Sn-Pb solders. These results suggest that the nonvolatile MTS may be a widespread characteristic of superconducting materials with flux trapping.