Observation of nonvolatile magneto-thermal switching in superconductors

TL;DR

This paper reports a novel nonvolatile magneto-thermal switching effect in superconductors, where thermal conductivity changes persist after removing the magnetic field, enabled by phase-separated superconducting states in Sn-Pb solders.

Contribution

It demonstrates a new nonvolatile thermal switching mechanism in superconductors using phase separation and flux distribution, expanding potential thermal management applications.

Findings

Nonvolatile thermal conductivity change observed in Sn-Pb solders.

Switching effect arises from phase-separated superconducting states.

Potential for active solid-state thermal management devices.

Abstract

Applying a magnetic field to a solid changes its thermal-transport properties. Although such magneto-thermal-transport phenomena are usually small effects, giant magneto-thermal resistance has recently been observed in spintronic materials1,2 and superconductors3,4, opening up new possibilities in thermal management technologies. However, the thermal conductivity conventionally changes only when a magnetic field is applied due to the absence of nonvolatility, which limits potential applications of thermal switching devices5,6. Here, we report the observation of nonvolatile thermal switching that changes the thermal conductivity when a magnetic field is applied and retains the value even when the field is turned off. This unconventional magneto-thermal switching, surprisingly, arises in commercial Sn-Pb solders and is realized by phase-separated superconducting states and resultant nonuniform magnetic flux distributions. This result confirms the versatility of the observed phenomenon and aids the development of active solid-state thermal management devices.