Spin-wave excitation by direct current in obliquely magnetized nanostructures |
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Authors: | RL Rodríguez-Suárez FM de Aguiar |
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Institution: | a Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 6904411, Chile b Departamento de Física, Universidade Federal de Pernambuco, Recife, Pernambuco 50670-901, Brazil |
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Abstract: | The magnetization dynamics of magnetic nanostructures magnetized at an arbitrary out-of-plane angle is investigated with the spin-wave formalism. The magnetic excitations driven by a spin-polarized direct current are considered to be standing spin-wave modes appropriate for nanopillar structures. The spin waves grow exponentially above a certain critical value of the current density and their post-threshold nonlinear dynamics leads to magnetization oscillations in the microwave range. Due to demagnetizing fields, the current-driven excitation strongly depends on the direction of the applied external magnetic field. In order to calculate the microwave oscillation frequency we derive an equation of motion for the spin-wave amplitude as a function of the out-of-plane angle of the applied field. The results are compared with recent experimental data as well as with another theoretical approach. |
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Keywords: | 75 30 Ds 75 40 Gb 72 25 Mk 72 25 Hg |
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