Spin information transfer and transport in hybrid spinmechatronic structures
JOINT EUROPEAN MAGNETIC SYMPOSIA (JEMS) 303 (2011) ARTN 012018
All-linear time reversal by a dynamic artificial crystal
Nature Communications 1:9 (2010)
Abstract:
The time reversal of pulsed signals or propagating wave packets has long been recognized to have profound scientific and technological significance. Until now, all experimentally verified time-reversal mechanisms have been reliant upon nonlinear phenomena such as four-wave mixing. In this paper, we report the experimental realization of all-linear time reversal. The time-reversal mechanism we propose is based on the dynamic control of an artificial crystal structure, and is demonstrated in a spin-wave system using a dynamic magnonic crystal. The crystal is switched from an homogeneous state to one in which its properties vary with spatial period a, while a propagating wave packet is inside. As a result, a linear coupling between wave components with wave vectors k≈π/a and k'=k-2π/a≈-π/a is produced, which leads to spectral inversion, and thus to the formation of a time-reversed wave packet. The reversal mechanism is entirely general and so applicable to artificial crystal systems of any physical nature. © 2010 Macmillan Publishers Limited. All rights reserved.Optical excitation of a forbidden magnetic resonance mode in a doped lutetium-iron-garnet film via the inverse Faraday effect
Physical Review Letters 105:10 (2010)
Abstract:
The effective magnetic field induced by a femtosecond pulse of circularly polarized light, via the inverse Faraday effect, is shown to excite a magnetic-dipole forbidden exchange spin resonance in a lutetium iron garnet. An external magnetic field cannot excite this mode, as the iron sublattices have the same gyromagnetic ratio and no net torque can be applied between them. However, since the sublattices have different magneto-optical susceptibilities, the inverse Faraday effect induces different effective fields on different iron sites, allowing excitation.Magnonic crystal based forced dominant wavenumber selection in a spin-wave active ring
Applied Physics Letters 96:8 (2010)
Abstract:
Spontaneous excitation of the dominant mode in a spin-wave active ring-a self-exciting positive-feedback system incorporating a spin-wave transmission structure-occurs at a certain threshold value of external gain. In general, the wavenumber of the dominant mode is extremely sensitive to the properties and environment of the spin-wave transmission medium, and is almost impossible to predict. In this letter, we report on a backward volume magnetostatic spin-wave active ring system incorporating a magnonic crystal. When mode enhancement conditions-readily predicted by a theoretical model-are satisfied, the ring geometry permits highly robust and consistent forced dominant wavenumber selection. © 2010 American Institute of Physics.Investigation of the femtosecond inverse Faraday effect using paramagnetic Dy3 Al5 O12
Physical Review B - Condensed Matter and Materials Physics 81:10 (2010)