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Kim JM, Kim SJ, Kang MG, Choi JG, Lee S, Park J, Van Phuoc C, Kim KW, Kim KJ, Jeong JR, Lee KJ, Park BG. Enhanced spin Seebeck effect via oxygen manipulation. Nat Commun 2023; 14:3365. [PMID: 37291127 PMCID: PMC10250387 DOI: 10.1038/s41467-023-39116-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/30/2023] [Indexed: 06/10/2023] Open
Abstract
Spin Seebeck effect (SSE) refers to the generation of an electric voltage transverse to a temperature gradient via a magnon current. SSE offers the potential for efficient thermoelectric devices because the transverse geometry of SSE enables to utilize waste heat from a large-area source by greatly simplifying the device structure. However, SSE suffers from a low thermoelectric conversion efficiency that must be improved for widespread application. Here we show that the SSE substantially enhances by oxidizing a ferromagnet in normal metal/ferromagnet/oxide structures. In W/CoFeB/AlOx structures, voltage-induced interfacial oxidation of CoFeB modifies the SSE, resulting in the enhancement of thermoelectric signal by an order of magnitude. We describe a mechanism for the enhancement that results from a reduced exchange interaction of the oxidized region of ferromagnet, which in turn increases a temperature difference between magnons in the ferromagnet and electrons in the normal metal and/or a gradient of magnon chemical potential in the ferromagnet. Our result will invigorate research for thermoelectric conversion by suggesting a promising way of improving the SSE efficiency.
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Affiliation(s)
- Jeong-Mok Kim
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Seok-Jong Kim
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
- Department of Physics, KAIST, Daejeon, 34141, Korea
| | - Min-Gu Kang
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Jong-Guk Choi
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Soogil Lee
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | | | - Cao Van Phuoc
- Department of Materials Science and Engineering, Chungnam National University, Daejeon, 34134, Korea
| | - Kyoung-Whan Kim
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea
| | - Kab-Jin Kim
- Department of Physics, KAIST, Daejeon, 34141, Korea
| | - Jong-Ryul Jeong
- Department of Materials Science and Engineering, Chungnam National University, Daejeon, 34134, Korea
| | - Kyung-Jin Lee
- Department of Physics, KAIST, Daejeon, 34141, Korea.
| | - Byong-Guk Park
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea.
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