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Merbouche H, Divinskiy B, Gouéré D, Lebrun R, El Kanj A, Cros V, Bortolotti P, Anane A, Demokritov SO, Demidov VE. True amplification of spin waves in magnonic nano-waveguides. Nat Commun 2024; 15:1560. [PMID: 38378662 PMCID: PMC10879122 DOI: 10.1038/s41467-024-45783-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 02/05/2024] [Indexed: 02/22/2024] Open
Abstract
Magnonic nano-devices exploit magnons - quanta of spin waves - to transmit and process information within a single integrated platform that has the potential to outperform traditional semiconductor-based electronics. The main missing cornerstone of this information nanotechnology is an efficient scheme for the amplification of propagating spin waves. The recent discovery of spin-orbit torque provided an elegant mechanism for propagation losses compensation. While partial compensation of the spin-wave losses has been achieved, true amplification - the exponential increase in the spin-wave intensity during propagation - has so far remained elusive. Here we evidence the operating conditions to achieve unambiguous amplification using clocked nanoseconds-long spin-orbit torque pulses in magnonic nano-waveguides, where the effective magnetization has been engineered to be close to zero to suppress the detrimental magnon scattering. We achieve an exponential increase in the intensity of propagating spin waves up to 500% at a propagation distance of several micrometers.
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Affiliation(s)
- H Merbouche
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - B Divinskiy
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - D Gouéré
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - R Lebrun
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - A El Kanj
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - V Cros
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - P Bortolotti
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - A Anane
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - S O Demokritov
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - V E Demidov
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany.
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Divinskiy B, Merbouche H, Demidov VE, Nikolaev KO, Soumah L, Gouéré D, Lebrun R, Cros V, Youssef JB, Bortolotti P, Anane A, Demokritov SO. Evidence for spin current driven Bose-Einstein condensation of magnons. Nat Commun 2021; 12:6541. [PMID: 34764266 PMCID: PMC8585877 DOI: 10.1038/s41467-021-26790-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 10/22/2021] [Indexed: 11/26/2022] Open
Abstract
The quanta of magnetic excitations - magnons - are known for their unique ability to undergo Bose-Einstein condensation at room temperature. This fascinating phenomenon reveals itself as a spontaneous formation of a coherent state under the influence of incoherent stimuli. Spin currents have been predicted to offer electronic control of Bose-Einstein condensates, but this phenomenon has not been experimentally evidenced up to now. Here we show that current-driven Bose-Einstein condensation can be achieved in nanometer-thick films of magnetic insulators with tailored nonlinearities and minimized magnon interactions. We demonstrate that, above a certain threshold, magnons injected by the spin current overpopulate the lowest-energy level forming a highly coherent spatially extended state. We quantify the chemical potential of the driven magnon gas and show that, at the critical current, it reaches the energy of the lowest magnon level. Our results pave the way for implementation of integrated microscopic quantum magnonic and spintronic devices.
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Affiliation(s)
- B Divinskiy
- Institute for Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - H Merbouche
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - V E Demidov
- Institute for Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany.
| | - K O Nikolaev
- Institute for Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - L Soumah
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - D Gouéré
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - R Lebrun
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - V Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Jamal Ben Youssef
- LABSTICC, UMR 6285 CNRS, Université de Bretagne Occidentale, 29238, Brest, France
| | - P Bortolotti
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - A Anane
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - S O Demokritov
- Institute for Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
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