| 1. |
- Balkashin, O. P., et al.
(author)
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Ferromagnetic resonance in copper-permalloy point contacts
- 2014
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In: Low temperature physics (Woodbury, N.Y., Print). - : AIP Publishing. - 1063-777X .- 1090-6517. ; 40:10, s. 929-936
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Journal article (peer-reviewed)abstract
- The response of copper-permalloy (Ni80Fe20) point microcontacts to microwave irradiation (8-12 GHz) is investigated systematically. The effects of the external magnetic field strength, transport current flowing through the contact, and microwave intensity and frequency on the measured signal are studied. The contributions to the contact electrical resistance owing to giant and anisotropic magnetoresistance are analyzed. The experimentally determined positions of the resonance features are in good agreement with Kittel's formula for FMR in films in parallel magnetic fields. The resonance signal is observed against the background of an additional contribution owing to rectification of the rf field on the nonlinear current-voltage characteristic of the contact. Two mechanisms for the resonance response are discovered: synchronous self-detection from mixing of the rf current with temporal variations in the resistance and a bolometric response associated with the steady-state variation in the contact resistance when magnetization precession is excited. The amplitude of the resonance signal is linearly proportional to the transport current through the contact and to the intensity of the microwave irradiation.
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| 2. |
- Balkashin, O. P., et al.
(author)
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Nonstationary magnetization dynamics of point contacts with a single ferromagnetic film
- 2009
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In: Low temperature physics (Woodbury, N.Y., Print). - : AIP Publishing. - 1063-777X .- 1090-6517. ; 35:8-9, s. 693-701
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Journal article (peer-reviewed)abstract
- The electric conductivity of point nanocontacts between 5, 10, and 100 nm thick ferromagnetic (F) cobalt films and a nonmagnetic (N) metal (copper or silver) needle is investigated. Two fundamentally different mechanisms for the formation of the response, signal to microwave irradiation have been observed for the first time. One mechanism is due to the effect of the rectification of high frequency ac current on the nonlinearity of the current-voltage characteristics due to the precession of the magnetization under the action of a constant transport current flowing through the contact. The second one is associated with the resonance excitation of the precession of the magnetization vector at the fundamental frequency and its harmonic by an external high-frequency field. The experimental results support a previous contention that a "surface spin valve" whose static and dynamic properties are similar to conventional F-1-N-F-2 spin valve [Nano Letters 7, 927 (2007)] is formed in the experimental F-N nanocontacts.
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| 3. |
- Balkashin, O. P., et al.
(author)
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Spin-valve effects in point contacts to exchange biased Co40Fe40B20 films
- 2014
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In: Low temperature physics (Woodbury, N.Y., Print). - : AIP Publishing. - 1063-777X .- 1090-6517. ; 40:10, s. 915-918
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Journal article (peer-reviewed)abstract
- Nonlinear current-voltage characteristics and magnetoresistance of point contacts between a normal metal (N) and films of amorphous ferromagnet (F) Co40Fe40B20 of different thickness, exchange-biased by antiferromagnetic Mn80Ir20 are studied. A surface spin valve effect in the conductance of such F-N contacts is observed. The effect of exchange bias is found to be inversely proportional to the Co40Fe40B20 film thickness. This behavior as well as other magneto-transport effects we observe on single exchange-pinned ferromagnetic films are similar in nature to those found in conventional three-layer spin-valves.
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