Speaker
Description
The interfacial Dzyaloshinskii-Moriya Interaction (iDMI) occurs at the surface between a ferromagnet and a heavy metal. In the past 15 years, it has led to interesting magnetic phenomena such as room temperature skyrmions and asymmetric domain wall motion. [1] Spin wave propagation is nonreciprocal when there is iDMI. That is, spin waves of the SAME frequency have different wavelengths when propagating left versus right. This has important applications in creating nonreciprocal microwave devices such as isolators and circulators.
In this talk, I will discuss our recent theoretical work on spin waves with iDMI, in two projects. In the first, I will discuss a weak but previously unknown quadratic dependence of spin wave frequencies on the iDMI strength. [2] Previously, spin wave frequencies were thought to depend linearly on the iDMI strength.
In the second, ways to generate nonreciprocal spin waves will be detailed, using a wire driving a microwave current. We develop a semi-analytic method for predicting the wire width, applied field strength and driving frequency which will maximise the nonreciprocity. [3] The results are confirmed using micromagnetic simulations.
Authors: Rair Macedo, Cameron McEleney, Ellen Lu, Robert Camley, Kristen Buchanan & Karen Livesey
[1] R.E. Camley and K.L. Livesey, Surf. Sci. Rep. 78, 100605 (2023)
[2] E. Lu, K.S. Buchanan and K.L. Livesey, Phys. Rev. B 111, 064432 (2025)
[3] C. McEleney, K.L. Livesey, R.E. Camley and R. Macedo, submitted (2026)
| Field of Condensed Matter | Magnetism |
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