Thermal Rectification in the Vicinity of a Structural Phase Transition

We have fabricated an oxide thermal rectifier made of La 1.98 Nd 0.02 CuO 4 and MnV 2 O 4 . By utilizing a jump of a thermal conductivity originated in the structural phase transition accompanied by the orbital ordering in MnV 2 O 4 , a rectifying coefficient of 1.14 has been achieved in the presence of a small temperature difference of 2 K. A thermal rectifier operating under a small temperature difference will play an important role for realizing heat-current control in electronic devices.