Ultra-high spin emission from antiferromagnetic FeRh

Fuente: arXiv
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Hauptverfasser: Hamara, Dominik, Strungaru, Mara, Massey, Jamie, Remy, Quentin, Antonio, Guillermo Nava, Santos, Obed Alves, Hehn, Michel, Evans, Richard F. L., Chantrell, Roy W., Mangin, Stéphane, Marrows, Christopher H., Barker, Joseph, Ciccarelli, Chiara
Format: Preprint
Veröffentlicht: 2024
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author Hamara, Dominik
Strungaru, Mara
Massey, Jamie
Remy, Quentin
Antonio, Guillermo Nava
Santos, Obed Alves
Hehn, Michel
Evans, Richard F. L.
Chantrell, Roy W.
Mangin, Stéphane
Marrows, Christopher H.
Barker, Joseph
Ciccarelli, Chiara
author_facet Hamara, Dominik
Strungaru, Mara
Massey, Jamie
Remy, Quentin
Antonio, Guillermo Nava
Santos, Obed Alves
Hehn, Michel
Evans, Richard F. L.
Chantrell, Roy W.
Mangin, Stéphane
Marrows, Christopher H.
Barker, Joseph
Ciccarelli, Chiara
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2404_07841
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Ultra-high spin emission from antiferromagnetic FeRh
Hamara, Dominik
Strungaru, Mara
Massey, Jamie
Remy, Quentin
Antonio, Guillermo Nava
Santos, Obed Alves
Hehn, Michel
Evans, Richard F. L.
Chantrell, Roy W.
Mangin, Stéphane
Marrows, Christopher H.
Barker, Joseph
Ciccarelli, Chiara
Materials Science
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.
title Ultra-high spin emission from antiferromagnetic FeRh
topic Materials Science
url https://arxiv.org/abs/2404.07841