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Lee JH, Choi WS, Jeen H, Lee HJ, Seo JH, Nam J, Yeom MS, Lee HN. Strongly Coupled Magnetic and Electronic Transitions in Multivalent Strontium Cobaltites. Sci Rep 2017; 7:16066. [PMID: 29167490 PMCID: PMC5700177 DOI: 10.1038/s41598-017-16246-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/13/2017] [Indexed: 12/21/2022] Open
Abstract
The topotactic phase transition in SrCoOx (x = 2.5–3.0) makes it possible to reversibly transit between the two distinct phases, i.e. the brownmillerite SrCoO2.5 that is a room-temperature antiferromagnetic insulator (AFM-I) and the perovskite SrCoO3 that is a ferromagnetic metal (FM-M), owing to their multiple valence states. For the intermediate x values, the two distinct phases are expected to strongly compete with each other. With oxidation of SrCoO2.5, however, it has been conjectured that the magnetic transition is decoupled to the electronic phase transition, i.e., the AFM-to-FM transition occurs before the insulator-to-metal transition (IMT), which is still controversial. Here, we bridge the gap between the two-phase transitions by density-functional theory calculations combined with optical spectroscopy. We confirm that the IMT actually occurs concomitantly with the FM transition near the oxygen content x = 2.75. Strong charge-spin coupling drives the concurrent IMT and AFM-to-FM transition, which fosters the near room-T magnetic transition characteristic. Ultimately, our study demonstrates that SrCoOx is an intriguingly rare candidate for inducing coupled magnetic and electronic transition via fast and reversible redox reactions.
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Affiliation(s)
- J H Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea.
| | - Woo Seok Choi
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Department of Physics, Sungkyunkwan University, Suwon, 440-746, Korea
| | - H Jeen
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Department of Physics, Pusan National University, Busan, 46241, Korea
| | - H-J Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - J H Seo
- School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - J Nam
- School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - M S Yeom
- Department of Applied Research and Network R&D, Center for Computational Science and Engineering, Division of National Supercomputing R&D, Korea Institute of Science and Technology Information (KISTI), 245 Daehak-ro, Daejeon, 34141, Republic of Korea.
| | - H N Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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