Phase-Field Modeling of Strain-Mediated Control of Nanomagnetism

Jia-Mian Hu, University of Wisconsin

October 20, 2020

Over the past decade, strain-mediated control of nanoscale magnetism has led to the discovery of many new science and new device concepts. Examples include strain-mediated 180° reversal of magnetization [1], strain-mediated unidirectional magnetic domain-wall motion [2], strain-mediated magnetoelectric random access memory [3], and beyond (see [4] for more examples). In this talk, two examples of our recent computational predictions on this topic will be presented, including (i) writing, deletion, and deformation of magnetic skyrmions by voltage-induced strains in magnetic nanostructures [5,6]; (ii) excitation and ultralong-distance (up to millimeters) transport of Terahertz magnons by femtosecond-laser-induced ultrafast strain pulses in magnetic heterostructures [7]. The computations were made by our in-house phase field models, which allow for coupling magnetization dynamics with either static or dynamic elasticity in elastically inhomogeneous systems. This capability is important to an accurate modeling of the strain-mediated control of magnetism in nanostructures where applied strains tend to relax; and in materials systems with strong spin-lattice coupling where the back-action of magnetization dynamics on the lattice are relatively significant.

[1] J.-M. Hu, et al., Nano Letters, 15, 616 (2015)
[2] J.-M. Hu, et al., Nano Letters, 16, 2341(2016)
[3] J.-M. Hu, et al., Nature Communications, 2, 1(2011)
[4] G. P. Carman, N. Sun, MRS Bulletin, 43, 822 (2018)
[5] J.-M. Hu, et al., npj Computational Materials, 4, 1(2017)
[6] J.-M. Hu, et al., Acta Materialia, 183, 145 (2020).
[7] S. Zhuang et al., arXiv preprint arXiv:2005.00629 (2020)