Room-temperature skyrmion lattice in a layered magnet (Fe<sub>0.5</sub>Co<sub>0.5</sub>)<sub>5</sub>GeTe<sub>2</sub>.

Zhang, Hongrui; Raftrey, David; Chan, Ying-Ting; Shao, Yu-Tsun; Chen, Rui; Chen, Xiang; Huang, Xiaoxi; Reichanadter, Jonathan T et al. · Sci Adv · 2022

basic_science · Level V

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Abstract

Novel magnetic ground states have been stabilized in two-dimensional (2D) magnets such as skyrmions, with the potential next-generation information technology. Here, we report the experimental observation of a Néel-type skyrmion lattice at room temperature in a single-phase, layered 2D magnet, specifically a 50% Co-doped Fe<sub>5</sub>GeTe<sub>2</sub> (FCGT) system. The thickness-dependent magnetic domain size follows Kittel's law. The static spin textures and spin dynamics in FCGT nanoflakes were studied by Lorentz electron microscopy, variable-temperature magnetic force microscopy, micromagnetic simulations, and magnetotransport measurements. Current-induced skyrmion lattice motion was observed at room temperature, with a threshold current density, <i>j</i><sub>th</sub> = 1 × 10<sup>6</sup> A/cm<sup>2</sup>. This discovery of a skyrmion lattice at room temperature in a noncentrosymmetric material opens the way for layered device applications and provides an ideal platform for studies of topological and quantum effects in 2D.