Ultra-high spin emission from antiferromagnetic FeRh

Dominik Hamara; Mara Strungaru; Jamie R. Massey; Quentin Remy; Xin Chen; Guillermo Nava Antonio; Obed Alves Santos; Michel Hehn; Richard F.L. Evans; Roy W. Chantrell; Stéphane Mangin; Caterina Ducati; Christopher H. Marrows; Joseph Barker; Chiara Ciccarelli

doi:10.1038/s41467-024-48795-z

Ultra-high spin emission from antiferromagnetic FeRh

Dominik Hamara, Mara Strungaru, Jamie R. Massey, Quentin Remy, Xin Chen, Guillermo Nava Antonio, Obed Alves Santos, Michel Hehn, Richard F.L. Evans, Roy W. Chantrell, Stéphane Mangin, Caterina Ducati, Christopher H. Marrows, Joseph Barker^*, Chiara Ciccarelli^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

An antiferromagnet emits spin currents when time-reversal symmetry is broken. This is typically achieved by applying an external magnetic field below and above the spin-flop transition or by optical pumping. In this work we apply optical pump-THz emission spectroscopy to study picosecond spin pumping from metallic FeRh as a function of temperature. Intriguingly we find that in the low-temperature antiferromagnetic phase the laser pulse induces a large and coherent spin pumping, while not crossing into the ferromagnetic phase. With temperature and magnetic field dependent measurements combined with atomistic spin dynamics simulations we show that the antiferromagnetic spin-lattice is destabilised by the combined action of optical pumping and picosecond spin-biasing by the conduction electron population, which results in spin accumulation. We propose that the amplitude of the effect is inherent to the nature of FeRh, particularly the Rh atoms and their high spin susceptibility. We believe that the principles shown here could be used to produce more effective spin current emitters. Our results also corroborate the work of others showing that the magnetic phase transition begins on a very fast picosecond timescale, but this timescale is often hidden by measurements which are confounded by the slower domain dynamics.

Original language	English
Article number	4958
Number of pages	8
Journal	Nature Communications
Volume	15
Issue number	1
Early online date	11 Jun 2024
DOIs	https://doi.org/10.1038/s41467-024-48795-z
Publication status	E-pub ahead of print - 11 Jun 2024

Bibliographical note

© The Author(s) 2024

Funding Information:
C.C. and J.B. acknowledge support from the Royal Society through University Research Fellowships. This project was supported by the Diamond Light Source and has received funding from the European Union\u2019s Horizon 2020 research and innovation programme under the Marie Sk\u0142odowska-Curie (grant agreement No. 861300) and the Engineering and Physical Sciences Research Council (grant numbers EP/V037935/1 and EP/X027074/1). Calculations were performed on ARC4, part of the High-Performance Computing facilities at the University of Leeds. CC thanks Dr. Samer Kurdi for the fruitful discussion. QR would like to thank Karel V\u00FDborn\u00FD for the fruitful discussion on ref. of the SI as well as for providing data necessary to get the interband conductivity (ref. in the SI).

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s41467-024-48795-z
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Hamara, D., Strungaru, M., Massey, J. R., Remy, Q., Chen, X., Nava Antonio, G., Alves Santos, O., Hehn, M., Evans, R. F. L., Chantrell, R. W., Mangin, S., Ducati, C., Marrows, C. H., Barker, J., & Ciccarelli, C. (2024). Ultra-high spin emission from antiferromagnetic FeRh. Nature Communications, 15(1), Article 4958. Advance online publication. https://doi.org/10.1038/s41467-024-48795-z

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title = "Ultra-high spin emission from antiferromagnetic FeRh",

abstract = "An antiferromagnet emits spin currents when time-reversal symmetry is broken. This is typically achieved by applying an external magnetic field below and above the spin-flop transition or by optical pumping. In this work we apply optical pump-THz emission spectroscopy to study picosecond spin pumping from metallic FeRh as a function of temperature. Intriguingly we find that in the low-temperature antiferromagnetic phase the laser pulse induces a large and coherent spin pumping, while not crossing into the ferromagnetic phase. With temperature and magnetic field dependent measurements combined with atomistic spin dynamics simulations we show that the antiferromagnetic spin-lattice is destabilised by the combined action of optical pumping and picosecond spin-biasing by the conduction electron population, which results in spin accumulation. We propose that the amplitude of the effect is inherent to the nature of FeRh, particularly the Rh atoms and their high spin susceptibility. We believe that the principles shown here could be used to produce more effective spin current emitters. Our results also corroborate the work of others showing that the magnetic phase transition begins on a very fast picosecond timescale, but this timescale is often hidden by measurements which are confounded by the slower domain dynamics.",

author = "Dominik Hamara and Mara Strungaru and Massey, {Jamie R.} and Quentin Remy and Xin Chen and {Nava Antonio}, Guillermo and {Alves Santos}, Obed and Michel Hehn and Evans, {Richard F.L.} and Chantrell, {Roy W.} and St{\'e}phane Mangin and Caterina Ducati and Marrows, {Christopher H.} and Joseph Barker and Chiara Ciccarelli",

note = "{\textcopyright} The Author(s) 2024 Funding Information: C.C. and J.B. acknowledge support from the Royal Society through University Research Fellowships. This project was supported by the Diamond Light Source and has received funding from the European Union\u2019s Horizon 2020 research and innovation programme under the Marie Sk\u0142odowska-Curie (grant agreement No. 861300) and the Engineering and Physical Sciences Research Council (grant numbers EP/V037935/1 and EP/X027074/1). Calculations were performed on ARC4, part of the High-Performance Computing facilities at the University of Leeds. CC thanks Dr. Samer Kurdi for the fruitful discussion. QR would like to thank Karel V\u00FDborn\u00FD for the fruitful discussion on ref. of the SI as well as for providing data necessary to get the interband conductivity (ref. in the SI). ",

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AU - Hamara, Dominik

AU - Strungaru, Mara

AU - Massey, Jamie R.

AU - Remy, Quentin

AU - Chen, Xin

AU - Nava Antonio, Guillermo

AU - Alves Santos, Obed

AU - Hehn, Michel

AU - Evans, Richard F.L.

AU - Chantrell, Roy W.

AU - Mangin, Stéphane

AU - Ducati, Caterina

AU - Marrows, Christopher H.

AU - Barker, Joseph

AU - Ciccarelli, Chiara

N1 - © The Author(s) 2024 Funding Information: C.C. and J.B. acknowledge support from the Royal Society through University Research Fellowships. This project was supported by the Diamond Light Source and has received funding from the European Union\u2019s Horizon 2020 research and innovation programme under the Marie Sk\u0142odowska-Curie (grant agreement No. 861300) and the Engineering and Physical Sciences Research Council (grant numbers EP/V037935/1 and EP/X027074/1). Calculations were performed on ARC4, part of the High-Performance Computing facilities at the University of Leeds. CC thanks Dr. Samer Kurdi for the fruitful discussion. QR would like to thank Karel V\u00FDborn\u00FD for the fruitful discussion on ref. of the SI as well as for providing data necessary to get the interband conductivity (ref. in the SI).

PY - 2024/6/11

Y1 - 2024/6/11

N2 - An antiferromagnet emits spin currents when time-reversal symmetry is broken. This is typically achieved by applying an external magnetic field below and above the spin-flop transition or by optical pumping. In this work we apply optical pump-THz emission spectroscopy to study picosecond spin pumping from metallic FeRh as a function of temperature. Intriguingly we find that in the low-temperature antiferromagnetic phase the laser pulse induces a large and coherent spin pumping, while not crossing into the ferromagnetic phase. With temperature and magnetic field dependent measurements combined with atomistic spin dynamics simulations we show that the antiferromagnetic spin-lattice is destabilised by the combined action of optical pumping and picosecond spin-biasing by the conduction electron population, which results in spin accumulation. We propose that the amplitude of the effect is inherent to the nature of FeRh, particularly the Rh atoms and their high spin susceptibility. We believe that the principles shown here could be used to produce more effective spin current emitters. Our results also corroborate the work of others showing that the magnetic phase transition begins on a very fast picosecond timescale, but this timescale is often hidden by measurements which are confounded by the slower domain dynamics.

AB - An antiferromagnet emits spin currents when time-reversal symmetry is broken. This is typically achieved by applying an external magnetic field below and above the spin-flop transition or by optical pumping. In this work we apply optical pump-THz emission spectroscopy to study picosecond spin pumping from metallic FeRh as a function of temperature. Intriguingly we find that in the low-temperature antiferromagnetic phase the laser pulse induces a large and coherent spin pumping, while not crossing into the ferromagnetic phase. With temperature and magnetic field dependent measurements combined with atomistic spin dynamics simulations we show that the antiferromagnetic spin-lattice is destabilised by the combined action of optical pumping and picosecond spin-biasing by the conduction electron population, which results in spin accumulation. We propose that the amplitude of the effect is inherent to the nature of FeRh, particularly the Rh atoms and their high spin susceptibility. We believe that the principles shown here could be used to produce more effective spin current emitters. Our results also corroborate the work of others showing that the magnetic phase transition begins on a very fast picosecond timescale, but this timescale is often hidden by measurements which are confounded by the slower domain dynamics.

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VL - 15

JO - Nature Communications

JF - Nature Communications

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ER -

Ultra-high spin emission from antiferromagnetic FeRh

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