A5059844362- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Topological Materials and Phenomena
- Magnetic and transport properties of perovskites and related materials
- Quantum and electron transport phenomena
- Advanced Condensed Matter Physics
- Theoretical and Computational Physics
- Advanced Memory and Neural Computing
- Magneto-Optical Properties and Applications
- Magnetic Field Sensors Techniques
- Atomic and Subatomic Physics Research
- ZnO doping and properties
- Neural Networks and Reservoir Computing
- Quantum optics and atomic interactions
- Geophysical and Geoelectrical Methods
- Cold Atom Physics and Bose-Einstein Condensates
- Nanoporous metals and alloys
- Photonic and Optical Devices
- Characterization and Applications of Magnetic Nanoparticles
- Supercapacitor Materials and Fabrication
- Mechanical and Optical Resonators
University of California, Los Angeles
2019-2025
University of Bath
2009
Spin-momentum locked surface states in topological insulators (TIs) provide a promising route for achieving high spin-orbit torque (SOT) efficiency beyond the bulk coupling heavy metals (HMs). However, previous works, there is huge discrepancy among quantitative SOTs from TIs various systems determined by different methods. Here, we systematically study SOT TI(HM)/Ti/CoFeB/MgO same method, and make conclusive assessment of HMs. Our results demonstrate that show more than one order magnitude...
Utilizing spin-orbit torque (SOT) to switch a magnetic moment provides promising route for low-power-dissipation spintronic devices. Here, the SOT switching of nearly compensated ferrimagnet Gdx (FeCo)1-x by topological insulator [Bi2 Se3 and (BiSb)2 Te3 ] is investigated at room temperature. The current density (1.20 × 105 A cm-2 ) more than one order magnitude smaller that in conventional heavy-metal-based structures, which indicates ultrahigh efficiency charge-spin conversion (>1) surface...
Symmetry breaking is a characteristic to determine which branch of bifurcation system follows upon crossing critical point. Specifically, in spin–orbit torque (SOT) devices, fundamental question arises: how can the symmetry perpendicular magnetic moment be broken by in-plane spin polarization? Here, we show that chiral antisymmetric Dzyaloshinskii–Moriya interaction (DMI) induce deterministic SOT switching magnetization. By introducing gradient saturation magnetization or anisotropy, dynamic...
Spin–orbit torque (SOT) switching of magnetization is a promising emerging technology for nonvolatile spintronic memory and logic applications. However, deterministic perpendicular with SOTs requires an additional symmetry breaking, which typically provided by external magnetic field, making it impractical In this work, we disclose that the insertion slightly asymmetric light-metal layer at heavy metal–ferromagnet interface SOT heterostructures, current-induced out-of-plane effective fields...
The Dzyaloshinskii-Moriya interaction (DMI) is an antisymmetric exchange that stabilizes spin chirality. One scientific and technological challenge understanding controlling the between chirality electric field. In this study, we investigate unconventional field effect on interfacial DMI, skyrmion helicity, dynamics in a system with broken inversion symmetry. We design heterostructures 3d-5d atomic orbital interface to demonstrate gate bias control of DMI energy thus transform opposite...
Abstract Achieving spin-pinning at the interface of hetero-bilayer ferromagnet/antiferromagnet structures in conventional exchange bias systems can be challenging due to difficulties control and weakening caused by poor quality. In this work, we propose an alternative approach stabilize interaction uncompensated antiferromagnet utilizing a gradient interlayer coupling. We demonstrate through designed field training protocol odd-layer topological MnBi 2 Te 4 . Our results reveal remarkable...
Abstract Magnetic skyrmions are topologically nontrivial chiral spin textures that have potential applications in next‐generation energy‐efficient and high‐density spintronic devices. In general, the spins of stabilized by noncollinear Dzyaloshinskii–Moriya interaction (DMI), originating from inversion symmetry breaking combined with strong spin–orbit coupling (SOC). Here, SOC topological insulators (TIs) is utilized to provide a large interfacial DMI TI/ferrimagnet heterostructures at room...
In transport, the topological Hall effect (THE) presents itself as nonmonotonic features (or humps and dips) in signal is widely interpreted a sign of chiral spin textures, like magnetic skyrmions. However, when anomalous (AHE) also present, coexistence two AHEs could give rise to similar artifacts, making it difficult distinguish between genuine THE with AHE two-component AHE. Here, we confirm by means transport magneto-optical Kerr (MOKE) microscopy, which skyrmions are directly observed,...
The chiral antiferromagnetic (AFM) materials, which have been widely investigated due to their rich physics, such as non-zero Berry phase and topology, provide a platform for the development of spintronics. Here, we find two distinctive anomalous Hall effect (AHE) contributions in AFM Mn
Abstract Stacking superconductors (SC) with ferromagnetic materials (FM) significantly impact superconductivity, enabling the emergence of spin‐triplet states and topological superconductivity. The tuning superconductivity in SC‐FM heterostructure is also reflected recently discovered superconducting diode effect, characterized by nonreciprocal electric transport when time inversion symmetries are broken. Notably, systems, a reversal operation reverses both current magnetization, leading to...
Topological insulators (TI) and magnetic topological (MTI) can apply highly efficient spin-orbit torque (SOT) manipulate the magnetization with their unique surface states (TSS) ultrahigh efficiency. Here, SOT switching of a hard MTI, V-doped (Bi,Sb)
Abstract Recent advances in using topological insulators (TIs) with ferromagnets (FMs) at room temperature have opened an innovative avenue spin‐orbit torque (SOT) nonvolatile magnetic memory and low dissipation electronics. However, direct integration of TIs perpendicularly magnetized FM, while retaining extraordinary charge‐to‐spin conversion efficiency ( > 100%), remains a major challenge. In addition, the indispensable thermal compatibility modern CMOS technologies has not yet been...
Current-induced spin–orbit torques (SOTs) in heavy metal/ferromagnet heterostructures have emerged as an efficient method for magnetization switching with applications nonvolatile magnetic memory and logic devices. However, experimental realization of SOT perpendicular requires additional inversion symmetry breaking, calling modifications the conventional heterostructures. In this work, we study SOTs deterministic by inserting different asymmetric dusting layers at interface. Similar to...
The charge current in a topological insulator (TI) will induce spin accumulation (Edelstein effect or EE), from which the be generated. Inversely, injection into TI called inverse Edelstein (IEE). Some experimental and theoretical works have been done for understanding of either EE IEE. However, little work incorporating both processes same sample has done. In this work, we propose phenomenological model to understand IEE TI-based system. Based on model, efficiencies can directly derived, is...
In conventional spintronic devices, ferromagnetic materials are used, which have a magnetization dynamics timescale of around nanoseconds, setting limit for the switching speed. Increasing speed has been one major challenges research. this work we take advantage ultrafast magnetic in ferrimagnetic instead ferromagnets, and use femtosecond laser pulses plasmonic photoconductive switch to create THz electrical by spin-orbit torque. By anomalous Hall magneto-optic Kerr effect (MOKE)...
We present a magnetic implementation of thermodynamic computing fabric. Magnetic devices within cores harness thermodynamics through its voltage-controlled thermal stability; while the evolution network states is guided by spin–orbit-torque effect. theoretically derive dynamics and show that fabric can successfully compute ground Boltzmann Machine. Subsequently, we demonstrate physical realization these based on CoFeB−MgO tunnel junction structure. The results this work pave path towards...
To further reduce the energy consumption in spin–orbit torque devices, it is crucial to precisely quantify (SOT) different materials and structures. In this work, heavy metal/ferromagnet metal/ferrimagnet heterostructures are employed as model systems compare electrical optical methods for SOT characterization, which based on anomalous Hall effect magneto-optical Kerr effect, respectively. It found that both yield consistent strength current-driven magnetization switching measurements...
Collinear antiferromagnetic (AFM) materials have unique promise of no stray fields, display ultrafast dynamics, and being robust against perturbation filed which motivates the extensive research spintronics. However, manipulation detection order remain formidable challenges. Here, we report electrical colinear antiferromagnetism in all-epitaxial RuO2/MgO/RuO2 three-terminal tunnel junctions (TJ) using spin-flop anisotropy magnetoresistance (TAMR). We measured a TAMR ratio around 60% at room...
Antiferromagnet is a promising candidate for the next generation spintronic devices, benefiting from its ultrafast dynamics and spontaneous zero stray field. However, understanding of their spin behaviors lacking due to challenges controlling/detecting quenched net magnetization. Unconventional compensated semiconducting antiferromagnets present strong time-reversal symmetry breaking, splitting in momentum space, suitable bandgap optical control/detection. Thus, it powerful platform uncover...
In transport, the topological Hall effect (THE) presents itself as non-monotonic features (or humps and dips) in signal is widely interpreted a sign of chiral spin textures, like magnetic skyrmions. However, when anomalous (AHE) also present, co-existence two AHEs could give rise to similar artifacts, making it difficult distinguish between genuine THE with AHE two-component AHE. Here we confirm by means transport magneto-optical Kerr (MOKE) microscopy, which skyrmions are directly observed,...