Magnetocaloric, magnetooptic thermal devices: thermal switches and refrigerators

Magnetic materials possess unique thermal properties that can give rise to powerful applications in thermal engineering. The magnetocaloric effect is the change in temperature of a magnetic material as a result of a change in its magnetization. Its primary application has been magnetic refrigerators, which have the potential to cool down to cryogenic temperatures and achieve better coefficient of performance (COP) than vapor-compression refrigerators. On the other hand, magnetic materials can be used control radiative heat transfer via magnetooptic effects in the infrared spectrum. Over the past decade, degenerately doped semiconductors and magnetic Weyl semimetals have been extensively studied for use in both far-field and near-field radiative heat transfer. In our recent work, we combined magnetocalorics and near-field magnetooptics to model a thermal switch where both the temperature delta and thermal conductance between two semi-infinite slabs can be magnetically controlled. In this talk, we discuss our ongoing work on modeling radiative heat transfer in magnetic refrigerators. Since radiation can transfer more entropy than conduction, we hypothesize that using radiation instead of conduction to reject heat can achieve a higher, magnetically controllable COP.