Seminars

Room Temperature Magnetic Skyrmions in Engineered Multilayer Films
  • 01:25pm April 4, 2017
  • B-75 Amundson Hall
  • Geoffrey Beach
  • Materials Science and Engineering
  • Massachusetts Intitute of Technology

Magnetic skyrmions [1] are particle-like chiral spin textures in the form of nanoscale vortices or bubbles that are topologically protected from being continuously ‘unwound’. Their topological nature gives rise to rich behaviors including ordered lattice formation, emergent electrodynamics and robust current-driven displacement at remarkably low current densities. However, magnetic skyrmions have until recently been restricted to just a few materials and observed only at low temperatures, limiting the experimental accessibility and technological application of these unique topological objects. This talk focuses on magnetic skyrmions in ultrathin ferromagnetic transition metal multilayers in which interfaces with heavy metals generate a strong Dzyaloshinskii-Moriya interaction (DMI) that can stabilize chiral magnetic order [2,3]. We show that in inversion-asymmetric engineered multilayer stacks can be used to stabilize magnetic skyrmions at room temperature. Using high-resolution x-ray microscopy, we reveal the current-driven dynamics of skyrmions in racetracks, demonstrate that skyrmions can be generated deterministically by nanosecond current pulses, and present an analytical framework to compute the properties of any skyrmion in any material, allowing large-scale multi-parameter-space studies of skyrmion properties and revealing new and unexpected behaviors. [1] U. Rößler, A. N. Bogdanov, C. Pfleiderer, C., Nature 442, 797-801 (2006) [2] S. Emori, et al., Nat. Mater. 12, 611–616 (2013). [3] S. Woo, et al., Nature Mater. 15, 501 (2016) [4] K. Litzius, et al., Nature Phys. 13, 170 (2017).

Seminars are open to alumni, friends of the Department, and the general public.

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