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Huang L, Lee SH, Kim SD, Shim JH, Shin HJ, Kim S, Park J, Park SY, Choi YS, Kim HJ, Hong JI, Kim DE, Kim DH. Universal field-tunable terahertz emission by ultrafast photoinduced demagnetization in Fe, Ni, and Co ferromagnetic films. Sci Rep 2020; 10:15843. [PMID: 32985564 PMCID: PMC7522994 DOI: 10.1038/s41598-020-72855-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 08/17/2020] [Indexed: 11/16/2022] Open
Abstract
We report a universal terahertz (THz) emission behavior from simple Ni, Fe, and Co metallic ferromagnetic films, triggered by the femtosecond laser pulse and subsequent photoinduced demagnetization on an ultrafast time scale. THz emission behavior in ferromagnetic films is found to be consistent with initial magnetization states controlled by external fields, where the hysteresis of the maximal THz emission signal is observed to be well-matched with the magnetic hysteresis curve. It is experimentally demonstrated that the ultrafast THz emission by the photoinduced demagnetization is controllable in a simple way by external fields as well as pump fluences.
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Affiliation(s)
- Lin Huang
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea
| | - Sang-Hyuk Lee
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea
| | - Seon-Dae Kim
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea
| | - Je-Ho Shim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Hee Jun Shin
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, South Korea
| | - Seongheun Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, South Korea
| | - Jaehun Park
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, South Korea
| | - Seung-Young Park
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon, 34133, South Korea
| | - Yeon Suk Choi
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon, 34133, South Korea
| | - Hyun-Joong Kim
- Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, South Korea
| | - Jung-Il Hong
- Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, South Korea
| | - Dong Eon Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Dong-Hyun Kim
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea.
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Shim JH, Syed AA, Kim JI, Piao HG, Lee SH, Park SY, Choi YS, Lee KM, Kim HJ, Jeong JR, Hong JI, Kim DE, Kim DH. Role of non-thermal electrons in ultrafast spin dynamics of ferromagnetic multilayer. Sci Rep 2020; 10:6355. [PMID: 32286462 PMCID: PMC7156415 DOI: 10.1038/s41598-020-63452-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 02/27/2020] [Indexed: 11/09/2022] Open
Abstract
Understanding of ultrafast spin dynamics is crucial for future spintronic applications. In particular, the role of non-thermal electrons needs further investigation in order to gain a fundamental understanding of photoinduced demagnetization and remagnetization on a femtosecond time scale. We experimentally demonstrate that non-thermal electrons existing in the very early phase of the photoinduced demagnetization process play a key role in governing the overall ultrafast spin dynamics behavior. We simultaneously measured the time-resolved reflectivity (TR-R) and the magneto-optical Kerr effect (TR-MOKE) for a Co/Pt multilayer film. By using an extended three-temperature model (E3TM), the quantitative analysis, including non-thermal electron energy transfer into the subsystem (thermal electron, lattice, and spin), reveals that energy flow from non-thermal electrons plays a decisive role in determining the type I and II photoinduced spin dynamics behavior. Our finding proposes a new mechanism for understanding ultrafast remagnetization dynamics.
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Affiliation(s)
- Je-Ho Shim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Akbar Ali Syed
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Jea-Il Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Hong-Guang Piao
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea.,College of Science, China Three Gorges University, Yichang, 443002, P. R. China
| | - Sang-Hyuk Lee
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea.,Division of Industrial Metrology, Korea Research Institute of Standards and Science, Daejeon, 34113, South Korea
| | - Seung-Young Park
- Spin Engineering Physics Team, Korea Basic Science Institute, Daejeon, 34133, South Korea
| | - Yeon Suk Choi
- Spin Engineering Physics Team, Korea Basic Science Institute, Daejeon, 34133, South Korea
| | - Kyung Min Lee
- Department of Material Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Daejeon, 34134, South Korea
| | - Hyun-Joong Kim
- Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, South Korea
| | - Jong-Ryul Jeong
- Department of Material Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Daejeon, 34134, South Korea
| | - Jung-Il Hong
- Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, South Korea
| | - Dong Eon Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea. .,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea.
| | - Dong-Hyun Kim
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea.
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Liu B, Niu W, Chen Y, Ruan X, Tang Z, Wang X, Liu W, He L, Li Y, Wu J, Tang S, Du J, Zhang R, Xu Y. Ultrafast Orbital-Oriented Control of Magnetization in Half-Metallic La 0.7 Sr 0.3 MnO 3 Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806443. [PMID: 30663164 DOI: 10.1002/adma.201806443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 12/15/2018] [Indexed: 06/09/2023]
Abstract
Manipulating spins by ultrafast pulse laser provides a new avenue to switch the magnetization for spintronic applications. While the spin-orbit coupling is known to play a pivotal role in the ultrafast laser-induced demagnetization, the effect of the anisotropic spin-orbit coupling on the transient magnetization remains an open issue. This study uncovers the role of anisotropic spin-orbit coupling in the spin dynamics in a half-metallic La0.7 Sr0.3 MnO3 film by ultrafast pump-probe technique. The magnetic order is found to be transiently enhanced or attenuated within the initial sub-picosecond when the probe light is tuned to be s- or p-polarized, respectively. The subsequent slow demagnetization amplitude follows the fourfold symmetry of the d x 2 - y 2 orbitals as a function of the polarization angles of the probe light. A model based on the Elliott-Yafet spin-flip scatterings is proposed to reveal that the transient magnetization enhancement is related to the spin-mixed states arising from the anisotropic spin-orbit coupling. The findings provide new insights into the spin dynamics in magnetic systems with anisotropic spin-orbit coupling as well as perspectives for the ultrafast control of information process in spintronic devices.
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Affiliation(s)
- Bo Liu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Wei Niu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Yongda Chen
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Xuezhong Ruan
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Zhixiong Tang
- Department of Physics, Nanjing University, Nanjing, 210093, P. R. China
| | - Xuefeng Wang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Wenqing Liu
- Department of Electronic Engineering, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK
| | - Liang He
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Yao Li
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Jing Wu
- York-Nanjing Joint Center in Spintronics, Department of Electronic Engineering and Department of Physics, The University of York, York, YO10 5DD, UK
| | - Shaolong Tang
- Department of Physics, Nanjing University, Nanjing, 210093, P. R. China
| | - Jun Du
- Department of Physics, Nanjing University, Nanjing, 210093, P. R. China
| | - Rong Zhang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Yongbing Xu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
- York-Nanjing Joint Center in Spintronics, Department of Electronic Engineering and Department of Physics, The University of York, York, YO10 5DD, UK
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