Micromagnetic simulations of spin wave interactions in comb-shaped structures

The field of magnonics consist of investigating the use of spin waves for magnetic devices. Spin waves are the propagating disturbances of magnetic moments in magnetic materials and can be used to transfer information without the Joule heating associated with conventional current. Understanding how spin waves interact in various geometric configurations can allow for the modulation or excitation of spin waves with specific frequencies or wavelengths. In the work presented here, we have investigated spin waves in rectangular (25 μm x 100 μm) comb-shaped Permalloy microstructures with micromagnetic simulations. The structures consist of two, three, four, and five teeth with different aspect ratios (teeth width/teeth separation) that converge into a large continuous region. Spin waves were excited in the teeth by reproducing the Oersted field generated by a microstrip antenna and observed in the surface wave and forward volume wave geometry. The spin waves that propagated into the continuous region show radial emission from the teeth, analogous to the diffraction of light in a multi-slit optical experiment. We will also discuss ongoing microwave and optical experimental work with similar structures that were fabricated with laser lithography.