Magneto-thermal-switching in type-I and type-II superconductors

Thermal switching by applying magnetic field is one of the key technologies in thermal management in electronic devices. In low-temperature devices, superconductors can be used as a magneto-thermal-switching (MTS) materials due to the large change in carrier thermal conductivity by the superconducting transition. In this study, we measured the temperature (T) and magnetic field (H) dependences of thermal conductivity (κ) of Sn, Ta and V to enrich knowledge on MTS of type-Ⅰ and type-Ⅱ superconductors. From the data analyses, we found different trends of κ-H curves in type-Ⅰ and type-Ⅱ superconductors. The normalized κ-H curves of type-Ⅰ superconductors showed the similar behavior, which is solely governed by Hc. However, the κ-H curves of type-Ⅱ superconductors were affected by the Hc1 and Hc2, and its behavior greatly depends on the materials. In addition, we investigated the elemental composition of Sn and Ta to explore the origin of weak hysteresis in the κ-H curves and revealed the importance of impurity on the hysteresis of κ-H curves.