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Generation and detection of phase-coherent current-driven magnons in magnetic multilayers
1Grenoble High Magnetic Field Laboratory, Max-Planck-Institut fur Festkorperforschung and Centre National de la Recherche Scientifique, France. tsoim@labs.polycnrs-gre.fr
Nature
|July 14, 2000
Summary
Researchers directly probed current-induced spin waves (magnons) in magnetic multilayers using microwaves. Findings support the feasibility of a spin-wave maser (SWASER) for novel electronic devices.
Area of Science:
- Condensed Matter Physics
- Spintronics
- Materials Science
Background:
- The magnetic state influences electrical transport in ferromagnets, exemplified by giant magnetoresistance.
- Current-induced magnetic perturbations in multilayers suggest spin wave (magnon) excitation.
Purpose of the Study:
- To directly investigate the high-frequency behavior and coherence of current-induced magnons.
- To determine the magnon spectrum and its dependence on excitation current.
- To assess the potential for a spin-wave maser (SWASER).
Main Methods:
- Utilized point contacts in magnetic multilayers.
- Applied external microwave irradiation to probe magnon dynamics.
- Analyzed magnon spectrum and amplitude variations with current.
Main Results:
- Directly observed and characterized current-induced magnons.
- Determined the magnon spectrum and its modulation by excitation current.
- Demonstrated partial phase coherence of the excited magnons.
Conclusions:
- The study provides direct evidence for current-induced spin waves.
- Observations support the concept of spin-wave amplification by stimulated emission of radiation (SWASER).
- Findings pave the way for novel spintronic devices based on magnonics.
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