Field-free switching of perpendicular magnetization through spin–orbit torque in FePt/[TiN/NiFe]₅ multilayers

Abstract

In order to maintain thermal stability of SOT devices with nanoscale size, it is desirable to achieve current induced magnetic switching in magnetic materials with high perpendicular anisotropy. In the...

Spin–Orbit Torque-Driven Memristor in L10 FePt Systems with Nanoscale-Thick Layers for Neuromorphic Computing

“…Recently, the bulk SOT within a single ferrimagnetic layer has been extensively investigated, and there is no limitation on the thickness of the ferromagnetic layer. − Therefore, it is desirable to explore the memristors in nanomaterials with bulk SOT effect. Recently, intermediate magnetic states can be observed in L1 0 FePt with large bulk SOT efficiency, and field-free SOT switching can be achieved in L1 0 FePt systems. − The tunable nonvolatile values of resistance is the typical feature for memristors and, until now, there have been no reports on spin-torque memristors based on the L1 0 FePt systems.…”

Tailoring Interlayer Chiral Exchange by Azimuthal Symmetry Engineering

“…11,12 Numerous solutions to this conundrum have been proposed, including the use of lateral symmetry breaking, 13−16 exchange coupling, 17−20 unconventional spins, 7,21,22 or geometry engineering. 23 These methods often generate new issues such as incompatibility with established magnetic tunnel junction (MTJ) fabrication processes, low magnetization switching ratio, 19,24 or low spin-conversion efficiency. 22 Recent calculations 25,26 and experimental verifications 27−32 have broadened the horizons of an antisymmetric Dzyaloshinskii−Moriya interaction (DMI) 33−36 from the conventional interfacial case 37−39 to a long-range interlayer scenario.…”

“…SOT-based magnetic random-access memory (SOT-MRAM), compared to conventional spin-transfer torque MRAM, enjoys key advantages such as higher operation speed, , improved endurance, , and potentially higher charge-to-spin conversion efficiency. − Currently, SOT-MRAM based on magnetization with perpendicular magnetic anisotropy (PMA) has been considered a prime candidate for the next generation nonvolatile random-access memory, due to its combination of high storage density and good thermal stability. ,− However, due to symmetry constraint, an in-plane polarized spin current cannot switch the PMA magnetization deterministically without an external in-plane field. , Numerous solutions to this conundrum have been proposed, including the use of lateral symmetry breaking, − exchange coupling, − unconventional spins, ,, or geometry engineering . These methods often generate new issues such as incompatibility with established magnetic tunnel junction (MTJ) fabrication processes, low magnetization switching ratio, , or low spin-conversion efficiency …”