Understanding current-driven dynamics of magnetic Néel walls in heavy metal/ferromagnetic metal/oxide trilayers

Abstract

We consider analytically current-driven dynamics of magnetic Néel walls in heavy metal/ferromagnetic metal/oxide trilayers where strong spin-orbit coupling and interfacial Dzyaloshinskii-Moriya interaction (i-DMI) coexist. We show that field-like spin-orbit torque (FL-SOT) with effective field along $\mathbf{n}\times \hat{\mathbf{J}}$ ($\mathbf{n}$ being the interface normal and $\hat{\mathbf{J}}$ being the charge current direction) and i-DMI induced torque can both lead to Walker breakdown suppression meanwhile leaving the wall mobility (velocity versus current density) unchanged. However, i-DMI itself can not induce the "universal absence of Walker breakdown" (UAWB) while FL-SOT exceeding a certain threshold can. Finitely-enlarged Walker limits before UAWB are theoretically calculated and well explain existing data. In addition, change in wall mobility and even its sign-inversion can be understood only if the anti-damping-like (ADL) SOT is appended. For Néel walls in ferromagnetic-metal layer with both perpendicular and in-plane anisotropies, we have calculated the respective modifications of wall mobility under the coexistence of spin-transfer torque, SOTs and i-DMI. Analytics shows that in trilayers with perpendicular anisotropy strong enough spin Hall angle and appropriate sign of i-DMI parameter can lead to sign-inversion in wall mobility even under small enough current density, while in those with in-plane anisotropy this only occurs for current density in a specific range.

22 pages, 4 figure

References in corpus (16)

• Matching domain wall configuration and spin-orbit torques for very efficient domain-wall motion
• Spin Transport at Interfaces with Spin-Orbit Coupling: Phenomenology
• Spin Transport at Interfaces with Spin-Orbit Coupling: Formalism
• High domain wall velocities induced by current in ultrathin Pt/Co/AlOx wires with perpendicular magnetic anisotropy
• Current-induced domain wall motion in Rashba spin-orbit system
• On the origin of field-like spin-orbit torques in heavy metal-ferromagnet-oxide thin film heterostructures
• High domain wall velocities due to spin currents perpendicular to the plane
• Interface enhanced spin-orbit torques and current-induced magnetization switching of Pd/Co/AlO${}_x$ layers
• Intraband and interband spin-orbit torques in non-centrosymmetric ferromagnets
• Current-induced motion of a transverse magnetic domain wall in the presence of spin Hall effect
• Spin-Orbit Torques in Two-Dimensional Rashba Ferromagnets
• Interfacial current-induced torques in Pt/Co/GdOx
• Universal Absence of Walker Breakdown and Linear Current-Velocity Relation via Spin-Orbit Torques in Coupled and Single Domain Wall Motion
• General planar transverse domain walls realized by optimized transverse magnetic field pulses in magnetic biaxial nanowires
• Engineering planar transverse domain walls in biaxial magnetic nanostrips by tailoring transverse magnetic fields with uniform orientation
• Optimal time-dependent polarized current pattern for fast domain wall propagation in nanowires: Exact solutions for biaxial and uniaxial anisotropies

Cited by in corpus (5)

• Determination of the Dzyaloshinskii-Moriya interactions
• Ultra-high differential mobility and velocity of Néel walls in spin valves with planar-transverse polarizers under low perpendicularly injected currents
• Stabilizing current-driven steady flows of 180${}^{\circ }$ domain walls in spin valves by interfacial Dzyaloshinskii-Moriya interaction
• Chiral domain wall dynamics in magnetic heterostructures with bulk Dzyaloshinskii-Moriya interactions
• Slonczewski-spin-current driven dynamics of 180${}^{\circ }$ domain walls in spin valves with interfacial Dzyaloshinskii-Moriya interaction