Jos Heremans, Ohio State professor of mechanical and aerospace engineering and CEM IRG-3 co-lead, along with an international team of researchers from North Carolina State University, Oak Ridge National Laboratory, and the Chinese Academy of Sciences, recently published the paper “Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe” in Science Advances.
The researchers found that local thermal perturbations of spins in a solid can convert heat to energy even in a paramagnetic material- where spins weren’t thought to correlate long enough to do so. This effect, which the researchers call “paramagnon drag thermopower,” converts a temperature difference into an electrical voltage. This discovery could lead to more efficient thermal energy harvesting.
“Before this work, it was believed that magnon drag could exist only in magnetically ordered materials, not in paramagnets,” said Prof. Heremans. “Because the best thermoelectric materials are semiconductors, and because we know of no ferromagnetic semiconductor at room temperature or above, we never thought before that magnon drag could boost the thermoelectric efficiency in practical applications. This new finding changes that completely; we can now investigate paramagnetic semiconductors, of which there are a lot.”
This research was supported in part by CEM. More information about this research and the team can be found in the press release from North Carolina State University. You can read the paper on the Science Advances website.