Seminars Archive

Nonvolatile magneto-thermal switching achieved using superconductors

Yoshikazu Mizuguchi
Department of Physics, Tokyo Metropolitan University

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 materials(1) and superconductors(2,3) 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 devices.(4) 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(5) 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. In the presentation, we will show various examples of superconductor that exhibits nonvolatile magneto-thermal switching. In addition, the expected collaborations with quantum-beam laboratories on the phenomena will be proposed. 1. Nakayama, H. et al. Above-room-temperature giant thermal conductivity switching in spintronic multilayer. Appl. Phys. Lett. 118, 042409 (2021). 2. Yoshida, M., Kasem, Md. R., Yamashita, A., Uchida, K. & Mizuguchi, Y. Magnetothermal-switching properties of superconducting Nb. Appl. Phys. Express 16, 033002 (2023). 3. Yoshida, M., Arima, H., Yamashita, A., Uchida, K. & Mizuguchi, Y. Large magnetothermal-switching ratio in superconducting Pb wires. arXiv:2305.08332. 4. Wehmeyer, G., Yabuki, T., Monachon, C., Wu, J. & Dames, C. Thermal diodes, regulators, and switches: Physical mechanisms and potential applications. Appl. Phys. Rev. 4, 041304 (2017). 5. Arima, H. et al. Observation of nonvolatile magneto-thermal switching in superconductors. arXiv: 2307.05957.