| 1. |
- Bonetti, Stefano, 1982-, et al.
(författare)
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Experimental evidence of self-localized and propagating spin wave modes in obliquely magnetized current-driven magnetic nanocontacts
- 2010
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 105:21, s. 217204-
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Tidskriftsartikel (refereegranskat)abstract
- Through detailed experimental studies of the angular dependence of spin wave excitations in nanocontact-based spin-torque oscillators, we demonstrate that two distinct spin wave modes can be excited, with different frequency, threshold currents, and frequency tunability. Using analytical theory and micromagnetic simulations we identify one mode as an exchange-dominated propagating spin wave, and the other as a self-localized nonlinear spin wave bullet. Wavelet-based analysis of the simulations indicates that the apparent simultaneous excitation of both modes results from rapid mode hopping induced by the Oersted field.
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| 2. |
- Sluka, Volker, et al.
(författare)
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Emission and propagation of 1D and 2D spin waves with nanoscale wavelengths in anisotropic spin textures
- 2019
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Ingår i: Nature Nanotechnology. - : Springer Nature. - 1748-3387 .- 1748-3395. ; 14:4, s. 328-333
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Tidskriftsartikel (refereegranskat)abstract
- Spin waves offer intriguing perspectives for computing and signal processing, because their damping can be lower than the ohmic losses in conventional complementary metal-oxide-semiconductor (CMOS) circuits. Magnetic domain walls show considerable potential as magnonic waveguides for on-chip control of the spatial extent and propagation of spin waves. However, low-loss guidance of spin waves with nanoscale wavelengths and around angled tracks remains to be shown. Here, we demonstrate spin wave control using natural anisotropic features of magnetic order in an interlayer exchange-coupled ferromagnetic bilayer. We employ scanning transmission X-ray microscopy to image the generation of spin waves and their propagation across distances exceeding multiples of the wavelength. Spin waves propagate in extended planar geometries as well as along straight or curved one-dimensional domain walls. We observe wavelengths between 1 mu m and 150 nm, with excitation frequencies ranging from 250 MHz to 3 GHz. Our results show routes towards the practical implementation of magnonic waveguides in the form of domain walls in future spin wave logic and computational circuits.
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| 3. |
- Zhou, Yan, et al.
(författare)
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Oscillatory transient regime in the forced dynamics of a nonlinear auto oscillator
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 82:1, s. 012408-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that the forced transient dynamics of a nonlinear (nonisochronous) auto-oscillator is qualitatively different from the dynamics of a quasilinear oscillator described by the classical Adler's model. If the normalized amplitude mu of the driving force exceeds a certain critical value mu(cr), the transition to the synchronized regime becomes oscillatory with a frequency proportional to proportional to root mu-mu(cr) and a synchronization time that is almost independent of mu. The discovered effect is illustrated on the example of a strongly nonlinear spin torque nano-oscillator (STNO) where the finite transient synchronization time can limit the possible range of STNO modulation frequencies.
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