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Impact of intragrai...
Impact of intragrain spin wave reflections on nanocontact spin torque oscillators
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- Åkerman, Johan (author)
- Gothenburg University,Göteborgs universitet,KTH,Tillämpad fysik,NanOsc AB, Electrum 205, S-16440 Kista, Sweden,Institutionen för fysik (GU),Department of Physics (GU)
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- Dvornik, M. (author)
- NanOsc AB, Electrum 205, S-16440 Kista, Sweden.
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- Qejvanaj, F. (author)
- NanOsc AB, Electrum 205, S-16440 Kista, Sweden.
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- Jiang, Sheng (author)
- KTH,Tillämpad fysik
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- Chung, Sunjae, 1976 (author)
- Gothenburg University,Göteborgs universitet,Institutionen för fysik (GU),Department of Physics (GU),Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;Korea Natl Univ Educ, Dept Phys Educ, Cheongju 28173, South Korea.
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- Åkerman, Johan, 1970 (author)
- Gothenburg University,Göteborgs universitet,Institutionen för fysik (GU),Department of Physics (GU)
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- Malm, Gunnar, 1972- (author)
- KTH,Elektroteknik
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(creator_code:org_t)
- American Physical Society (APS), 2021
- 2021
- English.
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In: Physical Review B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 103:21
- Related links:
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https://doi.org/10.1...
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https://gup.ub.gu.se...
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Abstract
Subject headings
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- We investigate the origin of the experimentally observed varying current-frequency nonlinearity of the propagating spin wave mode in nanocontact spin torque oscillators. Nominally identical devices with 100 nm diameter are characterized by electrical microwave measurements and show large variation in the generated frequency as a function of drive current. This quantitative and qualitative device-to-device variation is described in terms of continuous and discontinuous nonlinear transitions between linear current intervals. The thin-film grain microstructure in our samples is determined using atomic force and scanning electron microscopy to be on the scale of 30 nm. Micromagnetic simulations show that the reflection of spin waves against the grain boundaries results in standing wave resonance configurations. For a simulated device with a single artificial grain, the frequency increases linearly with the drive current until the decreased wavelength eventually forces another spin wave antinode to be formed. This transition results in a discontinuous step in the frequency versus current relation. Simulations of complete, randomly generated grain microstructures additionally shows continuous nonlinearity and a resulting device-to-device variation in frequency that is similar to the experimental levels. The impact of temperature from 4 to 300 K on the resonance mode-transition nonlinearity and frequency noise is investigated using simulations and it is found that the peak levels of the spectral linewidth as a function of drive current agree quantitatively with typical levels found in experiments at room temperature. The impact of the grain microstructure on the localized oscillation modes is also investigated. © 2021 authors.
Subject headings
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
- NATURVETENSKAP -- Fysik -- Den kondenserade materiens fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Condensed Matter Physics (hsv//eng)
Keyword
- Grain boundaries
- Microstructure
- Scanning electron microscopy
- Generated frequency
- Grain microstructure
- Impact of temperatures
- Localized oscillations
- Micromagnetic simulations
- Nonlinear transition
- Spectral line width
- Spin-torque oscillators
- Spin waves
Publication and Content Type
- ref (subject category)
- art (subject category)
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- By the author/editor
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Åkerman, Johan
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Dvornik, M.
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Qejvanaj, F.
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Jiang, Sheng
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Chung, Sunjae, 1 ...
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Åkerman, Johan, ...
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Malm, Gunnar, 19 ...
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- About the subject
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- NATURAL SCIENCES
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NATURAL SCIENCES
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and Physical Science ...
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- NATURAL SCIENCES
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NATURAL SCIENCES
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and Physical Science ...
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and Condensed Matter ...
- Articles in the publication
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Physical Review ...
- By the university
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University of Gothenburg
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Royal Institute of Technology