Kang L Wang
Layered materials have recently been investigated for exploring magnetic properties. This talk will discuss the magnetism of layered materials including those of magnetic doped materials as well the interface proximity-induced ferromagnetism by proximity with antiferromagnetic materials. We will begin by describing layered magnetic doped topological insulators (TI), SbBiTe, for achieving quantum anomalous Hall. Then we will discuss the proximity-induced magnetism in doped and undoped TIs when interfaced with different kinds of antiferromagnets, such as CrSb and MnTe, with a perpendicular and an in-plane Nel orders, respectively. Antiferromagnets interfaced with a magnet is shown being to yield skyrmions, whose topological charge can be controlled by cooling under applied magnetic fields. Atomically thin 2-D van der Waals magnetic materials (FeGeTe and alike) also have drawn significant interests. We observed interface Nel-type skyrmions in FeGeTe/WeTe2 heterostructures from the topological Hall effect below the temperature of 150 K, with the varying sizes for different temperatures, and the skyrmions were also confirmed by Lorentz transmission electron microscopy. A Dzyalosinskii-Moriya interaction with an energy of 1.0 mJ/m2, obtained from the aligned and stripe-like domain structure, is shown to be sufficiently large to support and stabilize the skyrmions.