UC Berkeley

The search for next-generation spintronic devices with ultrafast operation, low power consumption, and fully electrical functionality is a key frontier in condensed-matter physics and materials science, driven by the demand for energy-efficient and high-speed information technologies. Devices of antiferromagnetic (AFM) quantum materials are a promising platform owing to the fact that AFM do not produce stray magnetic fields making them viable to be more tightly packed, they possess ultrafast dynamics, and are robust to external magnetic perturbations. Intercalated transition-metal dichalcogenides (I-TMDs) provide a tunable platform for exploring electrically driven switching in low-dimensional materials. By inserting magnetic transition-metal ions into the van der Waals gaps of layered dichalcogenides, intercalation stabilizes long-range magnetic order and complex spin textures that are highly sensitive to composition and symmetry. Previous studies in FexNbS2, showed that electrical pulses could switch between two distinct resistance states. It was first proposed that electrical pulses would rotate an in-plane component of the Neel vector via spin-orbit transfer torque. Further studies determined that the electrical pulses rotate the principal nematic axis of the magnetic order via magnetoelastic coupling and not the reversal of the Neel vector via a spin-orbit transfer torque. This dissertation focuses on the current-induced switching mechanisms in Ni1/4TaSe2 and Co1/3TaS2. In Ni1/4TaSe2, devices exhibit current-induced magnetization reversal dominated by Joule-heating–assisted dynamics making it an all-electronic read-write scheme for magnetization recording. Electrical pulses in Co1/3TaS2, was seen to comb its helical magnetic texture enabling the ability to encode information. Together, these results demonstrate that current-induced switching in intercalated magnets arises from multiple, material-dependent mechanisms controlled by magnetic texture, lattice coupling, and dissipation pathways. This work clarifies when and why electrical switching is possible in frustrated AFM systems and establishes guiding principles for designing scalable, low-power spintronic devices.