Magnon-mediated thermal rectification with forward-bias and breakdown temperatures

Abstract

In an ideal model, a thermal rectifier is the thermal equivalent of the electrical diode. A device which leads a greater heat flow in one direction than another one. Currently used bulk and molecular mechanisms which can potentially result in thermal rectifying behavior have not evidenced that the rectification factor can reach one order of magnitude, which is an arbitrary limit required to deem the effect useful for engineered systems. Here, we have succeeded in building thermal diodes with thermal rectification factors up to 1.62 under 29 K temperature bias. Devices manipulate heat via the activation and deactivation of magnons in magnetic materials at room temperature through the Curie temperature. Furthermore, this factor can be enhanced further by improving the magnetic properties in the material and by increasing the thermal bias. In addition, thermal diodes present a well-defined breakdown as well as forward temperatures which control accurately the on state of the device. This approach paves the way to pursuit the one order limit at room temperature in a simple way and opens a new route towards the next generation of thermal devices.