Thermal rectification in jointless Pb solid wire

Abstract Thermal rectification is observed in jointless Pb wires at temperatures near the superconducting transition of Pb under magnetic fields. Using a different magnetic-field ( H ) response to the temperature dependence of the thermal conductivity ( κ – T ) under H // J and H ⊥ J where J is heat flow, we fabricated a jointless thermal diode. Thermal rectification is observed with a thermal rectification ratio (TRR) of 1.5 and the difference in κ of 330 W m −1 K −1 at T = 5.11 K under H = 400 Oe for a Pb wire with a 50%-bent ( H ⊥ J ) and 50%-straight ( H // J ) structure. The peak temperature of TRR can be tuned by the strength of the applied magnetic field. By changing the bending ratio to 40%-bent, a higher TRR exceeding two was observed. The Pb-jointless thermal diode will be a useful material for thermal management at cryogenic temperatures.