Room temperature skyrmions in layered magnet*

The Néel-type skyrmion is usually observed at room temperature in multilayer metal films. Polar single-phase magnets, with broken symmetries of spatial inversion and time reversal, are expected to host Néel-type skyrmion. However, their skyrmionic state has been observed only at low temperatures. In this talk, we demonstrated the experimental observation of a Néel-type skyrmion lattice at room temperature in a layered 2D magnet, 50% Co-doped Fe₅GeTe₂ (FCGT) system. We studied the evolution of skyrmion at various magnetic fields, temperatures, thicknesses, and current in FCGT nanoflakes using Lorentz electron microscopy, variable-temperature magnetic force microscopy, and magneto-transport measurements. The skyrmion can be stabilized in 100~300 nm nanoflake at the temperature range from 260~340 K. The current-induced skyrmion motion was realized at room temperature, with a threshold current density ~ 2.1 ×10⁶ A/cm^-2. This discovery of skyrmions at room temperature in a non-centrosymmetric material opens the way for layered device applications.