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arXiv · 2009.03654

Time refraction of spin waves

K. Schultheiss·N. Sato·P. Matthies·L. Körber·K. Wagner·T. Hula·O. Gladii·J. E. Pearson·A. Hoffmann·M. Helm·J. Fassbender·H. Schultheiss
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Abstract

We present an experimental study of time refraction of spin waves propagating in microscopic waveguides under the influence of time-varying magnetic fields. Using space- and time-resolved Brillouin light scattering microscopy, we demonstrate that the broken translational symmetry along the time coordinate can be used to in- or decrease the energy of spin waves during their propagation. This allows for a broadband and controllable shift of the spin-wave frequency. Using an integrated design of spin-wave waveguide and microscopic current line for the generation of strong, nanosecond-long, magnetic field pulses, a conversion efficiency up to 39% of the carrier spin-wave frequency is achieved, significantly larger compared to photonic systems. Given the strength of the magnetic field pulses and its strong impact on the spin-wave dispersion relation, the effect of time refraction can be quantified on a length scale comparable to the spin-wave wavelength. Furthermore, we utilize time refraction to excite spin-wave bursts with pulse durations in the nanosecond range and a frequency shift depending on the pulse polarity.

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K. Schultheiss, N. Sato, P. Matthies, L. Körber, K. Wagner, T. Hula, O. Gladii, J. E. Pearson, A. Hoffmann, M. Helm, J. Fassbender, H. Schultheiss. 2020-09-08. Time refraction of spin waves. https://doi.org/10.1103/physrevlett.126.137201

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