Tuning the High‐Efficiency Field‐Free Current‐Induced Deterministic Switching via Ultrathin PtMo Layer with Mo Content

Bekele, Zelalem Abebe; Li, Runze; Li, Yucai; Cao, Yi; Liu, Xionghua; Wang, Kaiyou

doi:10.1002/aelm.202100528

Cited by 20 publications

(10 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3 Constraints in symmetry require an effective in-plane magnetic field for SOTdriven deterministic switching of a ferromagnet with perpendicular magnetic anisotropy (PMA). 3,4 Much effort has been channeled to internalize this effective field, for instance, by exchange bias, 5,6 tilted anisotropy, 7,8 lateral SOT, 9 spin density gradient, 10−13 competing spin current, 14,15 and low-symmetry materials. 16,17 Interlayer exchange coupling (IEC) is another scheme for producing this symmetry-breaking magnetic field.…”

Section: Introductionmentioning

confidence: 99%

“…One increasingly popular choice is to utilize spin–orbit torque (SOT), which arises from either the spin Hall effect or the Rashba–Edelstein effect . Constraints in symmetry require an effective in-plane magnetic field for SOT-driven deterministic switching of a ferromagnet with perpendicular magnetic anisotropy (PMA). , Much effort has been channeled to internalize this effective field, for instance, by exchange bias, , tilted anisotropy, , lateral SOT, spin density gradient, − competing spin current, , and low-symmetry materials. , …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chiral Interlayer Exchange Coupling for Asymmetric Domain Wall Propagation in Field-Free Magnetization Switching

et al. 2023

View full text Add to dashboard Cite

The discovery of chiral spin texture has unveiled many unusual yet extraordinary physical phenomena, such as the Néel type domain walls and magnetic skyrmions. A recent theoretical study suggests that a chiral exchange interaction is not limited to a single ferromagnetic layer; instead, three-dimensional spin textures can arise from an interlayer Dzyaloshinskii–Moriya interaction. However, the influence of chiral interlayer exchange coupling on the electrical manipulation of magnetization has rarely been addressed. Here, the coexistence of both symmetric and chiral interlayer exchange coupling between two orthogonally magnetized CoFeB layers in PtMn/CoFeB/W/CoFeB/MgO is demonstrated. Images from polar magneto-optical Kerr effect microscopy indicate that the two types of coupling act concurrently to induce asymmetric domain wall propagation, where the velocities of domain walls with opposite chiralities are substantially different. Based on this microscopic mechanism, field-free switching of the perpendicularly magnetized CoFeB is achieved with a wide range of W thicknesses of 0.6–4.5 nm. This work enriches the understanding of interlayer exchange coupling for spintronic applications.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chiral Interlayer Exchange Coupling for Asymmetric Domain Wall Propagation in Field-Free Magnetization Switching

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Besides the abovementioned SCSs, Pt-based alloys , have been considered as the most competitive candidates to replace W due to their large spin Hall conductivity (SHC) (σ SH Pt ∼ 5.9 × 10 5 (ℏ/2e)Ω –1 ·m –1 ), large internal spin Hall ratio (θ SH Pt ∼ 0.8), and low thin-film resistivity (ρ xx Pt = 15–100 μΩ·cm) that can jointly result in a low power consumption for SOT switching. Several recent reports further pointed out that by introducing 3 d transition metals such as Cr into Pt, the overall ξ DL can be enhanced via the orbital Hall effect , or the intrinsic spin Hall effect .…”

Section: Introductionmentioning

confidence: 99%

Interfacial Engineering Strategies for Efficient Spin–Orbit Torque Devices with Pt Alloys

Chiu

Tsai

et al. 2023

ACS Appl. Electron. Mater.

View full text Add to dashboard Cite

To make spin−orbit torque magnetic randomaccess memories (SOT-MRAMs) become competitive enough to replace the contemporary memory architecture, it is of great importance to utilize conductive SOT materials that possess large damping-like spin−orbit torque (DL-SOT) efficiencies and backend-of-line (BEOL) compatibility. In this work, we report a BEOLcompatible CoFeB/MgO-based heterostructure with the Pt−Cr alloy as the spin current source (SCS) and inserted a Pt/Co/Pt composite layer to achieve texture decoupling and ferromagnetic coupling. A thermally robust perpendicular magnetic anisotropy (PMA) of the hybrid heterostructure can be retained after annealing at 400 °C for 1 h, while maintaining large DL-SOT efficiencies of the annealed Pt−Cr alloys (ξ DL ∼ 0.34 for Pt 0.70 Cr 0.30 ). Additionally, by optimizing the current distribution with a resistive Pt spacer layer, it is possible to simultaneously enhance the current-to-effective field conversion ratio (H z eff /I) and retain the apparent ξ DL (ξ DL ∼ 0.37 for Pt 0.79 Cr 0.21 ). Moreover, the critical switching current density can be reduced from J c Pt ∼ 2.0 × 10 7 A•cm −2 for Pt to J c Pt 0.70 Cr 0.30 ∼ 4.9 × 10 6 A•cm −2 for Pt 0.70 Cr 0.30 without tampering the thermal stability of the annealed heterostructure. These interfacial engineering strategies provide directions to integrate Pt-based SCSs with large ξ DL into a BEOL-compatible platform for future SOT-MRAM devices with PMA.

show abstract

“…Hence, the bulk SOT effect can be obtained in these alloys and multilayers, and its enhanced thermal stability can be acquired by increasing the thickness of the FM layer. For realizing deterministic switching of perpendicular magnetization, in-plane (IP) symmetry breaking induced by the external magnetic field, interface polarization electric field, competing spin current, exchange/interlayer coupling, or crystal asymmetry is essential. − Novel methods including the laser-induced lateral structure and three polarizations of a spin current are also proposed. , For example, field-free perpendicular magnetization switching induced by the bulk SOT is implemented in the CoPt alloy via the exchange and interlayer coupling from the antiferromagnetic/ferromagnetic structure . However, the additional layers impair the inherent advantages of a single layer structure, for example, process compatibility and fabrication costs.…”

Section: Introductionmentioning

confidence: 99%

Field-Free Magnetization Switching Induced by Bulk Spin–Orbit Torque in a (111)-Oriented CoPt Single Layer with In-Plane Remanent Magnetization

Zhang

Shen

et al. 2022

ACS Appl. Electron. Mater.

View full text Add to dashboard Cite

Spin–orbit torque (SOT)-induced perpendicular magnetization switching is one of the key solutions for the next generation of magnetic memory and spin logic applications. Recently, the bulk SOT effect in a single magnetic layer with a vertical composition gradient has attracted a lot of attention because it can break through the interfacial nature of the SOT effect in a traditional bilayer structure. However, the dependency of the external in-plane magnetic field or the additional pinning layer for deterministic switching hinders the further application of this technology. Here, for the first time, we implement field-free magnetization switching induced by bulk SOT in a single (111)-oriented CoPt magnetic layer with in-plane remanent magnetization. The initialized longitudinal in-plane remanent magnetization can substitute the external magnetic field to break the inversion symmetry and realize continuous field-free perpendicular magnetization switching. Furthermore, the in-plane remanent magnetization can be manipulated by the SOT effective field induced by lateral current pulses, leading to a tunable switching chirality. A multi-domain micromagnetic model is established to describe in depth the experimental observations and clarify the relationship between switching amplitude and easy magnetization cone angle. Our work provides an alternative solution to realize field-free perpendicular magnetization switching in a single magnetic layer, which can promote the development of emerging high-density and low-power SOT-based devices.

show abstract

Tuning the High‐Efficiency Field‐Free Current‐Induced Deterministic Switching via Ultrathin PtMo Layer with Mo Content

Cited by 20 publications

References 49 publications

Chiral Interlayer Exchange Coupling for Asymmetric Domain Wall Propagation in Field-Free Magnetization Switching

Chiral Interlayer Exchange Coupling for Asymmetric Domain Wall Propagation in Field-Free Magnetization Switching

Interfacial Engineering Strategies for Efficient Spin–Orbit Torque Devices with Pt Alloys

Field-Free Magnetization Switching Induced by Bulk Spin–Orbit Torque in a (111)-Oriented CoPt Single Layer with In-Plane Remanent Magnetization

Contact Info

Product

Resources

About