Spin–Orbit Torques and Magnetization Switching in (Bi,Sb)<sub>2</sub>Te<sub>3</sub>/Fe<sub>3</sub>GeTe<sub>2</sub> Heterostructures Grown by Molecular Beam Epitaxy
Thomas Guillet, Regina Galceran, Juan F. Sierra, Francisco J. Belarre, Belén Ballesteros, Marius V. Costache, Djordje Došenović, Hanako Okuno, A. Marty, Matthieu Jamet, Frédéric Bonell, Sergio O. Valenzuela
Abstract
Topological insulators (TIs) hold promise for manipulating the magnetization of a ferromagnet (FM) through the spin–orbit torque (SOT) mechanism. However, integrating TIs with conventional FMs often leads to significant device-to-device variations and a broad distribution of SOT magnitudes. In this work, we present a scalable approach to grow a full van der Waals FM/TI heterostructure by molecular beam epitaxy, combining the charge-compensated TI (Bi,Sb) 2 Te 3 with 2D FM Fe 3 GeTe 2 (FGT). Harmonic magnetotransport measurements reveal that the SOT efficiency exhibits a non-monotonic temperature dependence and experiences a substantial enhancement with a reduction of the FGT thickness to 2 monolayers. Our study further demonstrates that the magnetization of ultrathin FGT films can be switched with a current density of J c ∼ 10 10 A/m 2, with minimal device-to-device variations compared to previous investigations involving traditional FMs.