Spin Hall effect mediated current-induced deterministic switching in all-metallic perpendicularly magnetized Pt/Co/Pt trilayers

Deterministic Spin–Orbit Torque Switching by a Light-Metal Insertion

“…Nevertheless, the β values extracted using the loop shift method and the harmonics at large field method are in very good agreement with each other. Since the harmonics method results are obtained in the in-plane single- domain limit, we can rule out the role of preferential domain nucleation 33 and possible tilted anisotropies 34 in explaining the induction of H z eff and subsequent field-free switching in our samples.…”

Tailoring Interlayer Chiral Exchange by Azimuthal Symmetry Engineering

“…The spin–orbit torque (SOT) originating from the spin current generated from either the spin-Hall effect or the Rashba effect has the capability to electrically manipulate magnetic moments. 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 …”

Field-Free Spin–Orbit Torque Switching via Oscillatory Interlayer Dzyaloshinskii–Moriya Interaction for Advanced Memory Applications

“…Despite a lower J c , the behavior is memristive, achieving only a 40% switching. On the other hand, for the tilted anisotropy case demonstrated by Vineeth Mohanan P et al, J c ≈ 1.5 × 10 11 A/m 2 is reported. However, the feasibility of employing such thickness-gradient-induced easy axis tilting in a pillar-shaped device is unknown.…”

“…This can be achieved by introducing either an in-plane magnetized layer ,, or an antiferromagnetic layer , with magnetization aligned parallel to the current direction. Researchers have also devised heterostructures with inherent bias fields, including the stray field of the in-plane layer, the orange peel effect, , and tilted anisotropy. ,, However, the resulting SOT efficiency of these solutions typically falls short compared to the saturated value when a large H x is applied, leading to a suboptimized switching behavior and large power consumption. ,,, On another front, the antisymmetric Dzyaloshinskii–Moriya interaction (DMI), , which enables noncollinear chiral spin configurations, has piqued increasing interest. DMI relies on breaking inversion symmetry in the material and strong SOC. , When an in-plane symmetry-breaking element is added, long-range “interlayer” DMI (i-DMI) with a three-dimensional (3D) conformation has also been identified, where two ferromagnetic atoms exist in separate layers. − This chiral interlayer-coupling effect is pivotal in the realm of multilayered spintronic devices, particularly those employing dual PMA layers ,, or a combination of one PMA layer and an in-plane magnetized layer , (orthogonally magnetized systems).…”

“…Researchers have also devised heterostructures with inherent bias fields, including the stray field of the in-plane layer, 21 the orange peel effect, 16,20 and tilted anisotropy. 24,26,27 However, the resulting SOT efficiency of these solutions typically falls short compared to the saturated value when a large H x is applied, leading to a suboptimized switching behavior and large power consumption. 17,20,21,26 On another front, the antisymmetric Dzyalosh- inskii−Moriya interaction (DMI), 28,29 which enables noncollinear chiral spin configurations, has piqued increasing interest.…”