Electric field control of spin-orbit torque switching in a spin-orbit ferromagnet single layer

Abstract To achieve a desirable magnitude of spin-orbit torque (SOT) switching and realise multifunctional spin logic and memory devices utilising SOT, controlling the SOT manipulation is vitally important. In conventional SOT bilayer systems, researchers have tried to control the switching behaviour via interfacial oxidisation; however, the switching efficiency is limited by the interface quality. A current-induced effective magnetic field in a single layer of a ferromagnet with strong spin-orbit interactions, the so-called spin-orbit ferromagnet, can be utilised to induce SOT. In spin-orbit ferromagnet systems, electric field application has potential for manipulating the spin-orbit interactions via carrier concentration modulation. In this work, we demonstrate that SOT switching can be successfully controlled via an external electric field using a (Ga,Mn)As single layer. By applying a gate voltage, the switching current density can be solidly and reversibly manipulated with a large ratio of 14.5%, which is ascribed to the successful modulation of the interfacial electric field. Our findings help further the understanding of the magnetisation switching mechanism and advance the development of gate-controlled SOT devices.

Download Full-text

Electric-Field Control of Spin–Orbit Torques in WS2/Permalloy Bilayers

ACS Applied Materials & Interfaces ◽

10.1021/acsami.7b16919 ◽

2018 ◽

Vol 10 (3) ◽

pp. 2843-2849 ◽

Cited By ~ 23

Author(s):

Weiming Lv ◽

Zhiyan Jia ◽

Bochong Wang ◽

Yuan Lu ◽

Xin Luo ◽

...

Keyword(s):

Electric Field ◽

Spin Orbit ◽

Field Control

Download Full-text

Plasmon modes in N-layer silicene structures

Journal of Physics Condensed Matter ◽

10.1088/1361-648x/ac3c66 ◽

2021 ◽

Author(s):

Men Nguyen Van

Keyword(s):

Electric Field ◽

Random Phase ◽

Single Layer ◽

Plasmon Mode ◽

Orbit Coupling ◽

Collective Excitations ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Number Of Layers ◽

Plasmon Modes

Abstract We investigate the plasmon properties in N-layer silicene systems consisting of N, up to 6, parallel single-layer silicene under the application of an out-of-plane electric field, taking into account the spin-orbit coupling within the random-phase approximation. Numerical calculations demonstrate that N undamped plasmon modes, including one in-phase optical and (N-1) out-of-phase acoustic modes, continue mainly outside the single-particle excitation area of the system. As the number of layers increases, the frequencies of plasmonic collective excitations increase and can become much larger than that in single layer silicene, more significant for high-frequency modes. The optical (acoustic) plasmon mode(s) noticeably (slightly) decreases with the increase in the bandgap and weakly depends on the number of layers. We observe that the phase transition of the system weakly affects the plasmon properties, and as the bandgap caused by the spin-orbit coupling equal that caused by the external electric field, the plasmonic collective excitations and their broadening function in multilayer silicene behave similarly to those in multilayer gapless graphene structures. Our investigations show that plasmon curves in the system move toward that in single layer silicene as the separation increases, and the impacts of this factor can be raised by a large number of layers in the system. Finally, we find that the imbalanced carrier density between silicene layers significantly decreases plasmon frequencies, depending on the number of layers.

Download Full-text

Physics of Spin-Orbit-Coupled Oxides

10.1093/oso/9780199602025.001.0001 ◽

2021 ◽

Author(s):

Gang Cao ◽

Lance DeLong

Keyword(s):

Giant Magnetoresistance ◽

Degrees Of Freedom ◽

High Temperature Superconductivity ◽

Transition Element ◽

Spin Orbit ◽

Transition Elements ◽

Crystalline Electric Field ◽

Magnetic Exchange ◽

Spin Orbit Interactions ◽

Strong Spin

Prior to 2010, most research on the physics and chemistry of transition metal oxides was dominated by compounds of the 3d-transition elements such as Cr, Mn, Fe, Co, Ni, and Cu. These materials exhibited novel, important phenomena that include giant magnetoresistance in manganites, as well as high-temperature superconductivity in doped La2CuO4 and related cuprates. The discovery in 1994 of an exotic superconducting state in Sr2RuO4 shifted some interest toward ruthenates. Moreover, the realization in 2008 that a novel variant of the classic Mott metal-insulator transition was at play in Sr2IrO4 provided the impetus for a burgeoning group of studies of the influence of strong spin-orbit interactions in “heavy” (4d- and 5d-) transition-element oxides. This book reviews recent experimental and theoretical evidence that the physical and structural properties of 4d- and 5d-oxides are decisively influenced by strong spin-orbit interactions that compete or collaborate with comparable Coulomb, magnetic exchange, and crystalline electric field interactions. The combined effect leads to unusual ground states and magnetic frustration that are unique to this class of materials. Novel couplings between the orbital/lattice and spin degrees of freedom, which lead to unusual types of magnetic order and other exotic phenomena, challenge current theoretical models. Of particular interest are recent investigations of iridates and ruthenates focusing on strong spin-orbit interactions that couple the lattice and spin degrees of freedom.

Download Full-text

Enhanced optical spatial differential operations via strong spin-orbit interactions in an anisotropic epsilon-near-zero slab

Physical Review A ◽

10.1103/physreva.104.053513 ◽

2021 ◽

Vol 104 (5) ◽

Author(s):

Wenhao Xu ◽

Xiaohui Ling ◽

Dingyu Xu ◽

Shizhen Chen ◽

Shuangchun Wen ◽

...

Keyword(s):

Spin Orbit ◽

Spin Orbit Interactions ◽

Strong Spin ◽

Epsilon Near Zero

Download Full-text

Electric-field control of field-free spin-orbit torque switching via laterally modulated Rashba effect in Pt/Co/AlOx structures

10.21203/rs.3.rs-87924/v1 ◽

2020 ◽

Author(s):

Min-Gu Kang ◽

Jong-Guk Choi ◽

Jimin Jeong ◽

Jae Yeol Park ◽

Hyeon-Jong Park ◽

...

Keyword(s):

Electric Field ◽

Coupling Effect ◽

Spin Orbit ◽

Rashba Effect ◽

Oxide Interface ◽

Electrical Control ◽

Perpendicular Magnetization ◽

Field Control ◽

Out Of Plane ◽

Logic Operations

Abstract Spin-orbit coupling effect in structures with broken inversion symmetry, known as the Rashba effect, facilitates spin-orbit torques (SOTs) in heavy metal/ferromagnet/oxide structures, along with the spin Hall effect. Electric-field control of the Rashba effect is established for semiconductor interfaces, but it is challenging in structures involving metals owing to the screening effect. Here, we report that the Rashba effect in Pt/Co/AlOx structures is laterally modulated by electric voltages, generating out-of-plane SOTs. This enables field-free switching of the perpendicular magnetization and electrical control of the switching polarity. Changing the gate oxide reverses the sign of out-of-plane SOT while maintaining the same sign of voltage-controlled magnetic anisotropy, which confirms the Rashba effect at the Co/oxide interface is a key ingredient of the electric-field modulation. The electrical control of SOT switching polarity in a reversible and non-volatile manner can be utilized for programmable logic operations in spintronic logic-in-memory devices.

Download Full-text