Excitations in magnetic materials, such as domain walls and skyrmions, provide a rich playground for studying intriguing physical phenomena such as chirality, magnetization dynamics, and spin-orbit coupling. Additionally, they also hold vast technological potential. Domain walls and skyrmions, which can be translated by currents across racetrack-like wire devices, provide a promising approach to encode bits of information for next-generation memory and logic. One technological and scientific challenge is to stabilize small spin textures and move them efficiently with high velocities. This is critical for dense, fast memory and logic. However, in ferromagnetic materials, current-driven spin texture dynamics face an intrinsic “speed limit,” and room-temperature-stable magnetic skyrmions are an order of magnitude too large to be useful in any competitive technologies. Here, by synthesizing and engineering a new class of materials– compensated chiral ferrimagnets– we overcome these fundamental limitations plaguing traditional spintronic systems. Moreover, by using advanced electrical and optical techniques (and developing new ones), we show that these systems provide a new platform to study complex fundamental phenomena like topology, interface interactions, and even relativistic dynamics.

[1] Relativistic kinematics of a magnetic soliton, Science, vol. 18, p. 1438-1442 (2020).