Room temperature magnetization switching in topological insulator-ferromagnet heterostructures by spin-orbit torques

Abstract

Topological insulators with spin-momentum-locked topological surface states are expected to exhibit a giant spin-orbit torque in the topological insulator/ferromagnet systems. To date, the topological insulator spin-orbit torque-driven magnetization switching is solely reported in a Cr-doped topological insulator at 1.9 K. Here we directly show giant spin-orbit torque-driven magnetization switching in a Bi2Se3/NiFe heterostructure at room temperature captured using a magneto-optic Kerr effect microscope. We identify a large charge-to-spin conversion efficiency of ~1–1.75 in the thin Bi2Se3 films, where the topological surface states are dominant. In addition, we find the current density required for the magnetization switching is extremely low, ~6 × 105 A cm–2, which is one to two orders of magnitude smaller than that with heavy metals. Our demonstration of room temperature magnetization switching of a conventional 3d ferromagnet using Bi2Se3 may lead to potential innovations in topological insulator-based spintronic applications.

Towards microscopic control of the magnetic exchange coupling at the surface of a topological insulator

“…Topological insulators (TIs) define a novel state of electronic matter, characterized by the coexistence of a bulk insulating gap and a non-degenerate metallic surface band. The interplay between TIs and magnetism is of great interest for future spintronics and low power devices [1][2][3][4]. In particular the discovery of the quantum anomalous Hall effect (QAHE) [5] led to intense research activities in magnetically doped TIs.…”

A generic method to control hysteresis and memory effect in Van der Waals hybrids

“…MoS 2 is one of the most important members of the transition metal-dichalcogenide family, and has found numerous applications in electronics, optoelectronics, piezoelectricity, and valleytronics [7,[19][20][21][22][23]. The diverse properties of these materials have been best exploited by fabricating hybrids out of them, by stacking one on top of the other, leading to state-of-the-art sensors, and providing a solid platform for further miniaturization of devices and faster electronics [8,9,16,18,19,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42].…”

Spin-charge conversion in NiMnSb Heusler alloy films

“…The spin-charge conversion in well-designed materials and/or new states of matter is essential for the development of future energy-efficient spintronic devices (1)(2)(3)(4)(5)(6)(7). Recently, spin currents generated from ferromagnets (FMs), such as CoFeB (8,9), NiFe (9)(10)(11), and FePt (12), is attracting great attention not only due to the remarkable spin signals but also due to their controllability owing to interactions between spin and magnetization.…”