Spin-Wave Optics: Refraction and Imaging
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Beschreibung
In this thesis the diffraction and refraction of spin waves is studied; measurements are conducted using a time-resolved scanning Kerr microscope.
In the first part of this thesis, we discuss the diffraction of Damon-Eshbach type spin-waves on an array of slits and on a double slit in a thin Permalloy film. We observe distinct diffraction patterns behind the slits which form replications of the spin-wave distribution inside the slits. These images arise from the anisotropic spin-wave dispersion. We show that it is possible to tune position and shape of the images by changing an externally applied magnetic field or the frequency of the spin waves. We reproduce the observed spin-wave patterns well by superimposing those Fourier components of the respective slit patterns which are allowed to propagate in the Permalloy film by the dispersion relation.
The second part of this thesis introduces the refraction of spin waves on a step edge formed by two Permalloy films of different thickness. We show in this thesis that such a system induces the refraction of spin waves and study the dependence of the refraction angle and the wavelength on the frequency of the spin wave.
Autor*in
Sebastian Mansfeld