A team of researchers, affiliated with UNIST, recently introduced a new class of magnetic materials for spin caloritronics. Published in the February 2021 issue of Nature communications, the demonstrated STE applications of a new class of magnets will pave the way for versatile recycling of ubiquitous waste heat. This breakthrough was led by Professor Jung-Woo Yoo and his research team at the Department of Materials Science and Engineering at UNIST.
Spin thermoelectrics is an emerging thermoelectric technology that allows energy to be recovered from waste heat. This has generated substantial research interest with the potential benefits of scalability and energy conversion efficiency, through orthogonal paths for heat and charge flow. However, magnetic insulators previously used for spin thermoelectrics have scaling issues due to high-temperature processing and difficulties with deposition on large areas, the research team noted.
In this study, the research team introduced a molecule-based magnet, Cr-PBA, as an AC magnetic insulator for magnon-mediated thermal-electric energy conversion. According to the research team, the studied molecular magnetic film exhibits several advantageous characteristics over inorganic magnetic insulators in terms of TE spin applications (STE). Indeed, this involves versatile synthetic pathways that can be deposited over a large area at room temperature, in addition to low spin-lattice interaction and low thermal conductivity.
“The growth of Cr-PBA was performed at room temperature using the electrochemical deposition (ECD) method, which could offer scalable production of thin films,” noted the research team. “This deposition technique can be easily adapted for large area and mass production of thin films, which can boast a significant advantage of STE, namely scalability over large areas.”
According to the research team, various other methodologies, such as painting and printing, can also be used to develop the PBA film. They also noted that the generation and transfer of magnons are essential processes for STE energy harvesting, as well as for magnon information technology. Experimental results also indicated that the excitations of low-energy magnons in this class of magnets were much stronger than those of typical inorganic magnets. Additionally, ferromagnetic resonance studies have shown an extremely low Gilbert damping constant, indicating low loss of heat-generated magnons. Additionally, the low thermal conductivity determined in the molecular-based magnetic film studied is an ancillary benefit for STE energy harvesting as it helps maintain a higher temperature gradient across the film, the team noted. research.
“Our study shows that the excitations and magnon transfers in this hybrid magnet are very efficient, suggesting that molecule-based magnets, along with their synthetic versatility, could be outstanding alternatives for various spin caloritronic applications. as well as magnon spintronics, ”the research team said. .
The results of this research were published in the February 2021 issue of Nature communications. This study was jointly conducted by Professor Joonki Suh (Department of Materials Science and Engineering, UNIST), Professor Byoung-Chul Min (Korea Institute of Science and Technology, KIST) and two graduates from the Department of Science and from UNIST Materials Engineering – Dr Jungmin Park (KBSI) and Professor Mi-Jin Jin (Dankook University).
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Material provided by Ulsan National Institute of Science and Technology (UNIST). Original written by JooHyeon Heo. Note: Content can be changed for style and length.