A5004773969- Magnetic properties of thin films
- Advanced Memory and Neural Computing
- Quantum and electron transport phenomena
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- ZnO doping and properties
- Magnetic Properties and Applications
- Magneto-Optical Properties and Applications
- Ferroelectric and Negative Capacitance Devices
- Multiferroics and related materials
- Magnetic Field Sensors Techniques
- Theoretical and Computational Physics
- Magnetic Properties of Alloys
- Characterization and Applications of Magnetic Nanoparticles
- Neural Networks and Reservoir Computing
- Heusler alloys: electronic and magnetic properties
- Semiconductor materials and devices
- Photonic and Optical Devices
- Advanced Thermoelectric Materials and Devices
- Electronic and Structural Properties of Oxides
- Topological Materials and Phenomena
- Magnetic Properties and Synthesis of Ferrites
- Photonic Crystals and Applications
- Force Microscopy Techniques and Applications
- Physical Unclonable Functions (PUFs) and Hardware Security
Korea Advanced Institute of Science and Technology
2016-2025
Kootenay Association for Science & Technology
2021-2024
Chungnam National University
2014-2024
University of Ulsan
2021
Hitachi (United Kingdom)
2010
Spin transistors and spin Hall effects have been two separate leading directions of research in semiconductor spintronics which seeks new paradigms for information processing technologies. We brought the together to realize an all-semiconductor effect transistor. Our scheme circumvents semiconductor-ferromagnet interface problems original Datta-Das transistor concept demonstrates utility microelectronics. The devices use diffusive transport operate without electrical current, i.e., Joule...
We theoretically investigate the dynamics of antiferromagnetic domain walls driven by spin-orbit torques in antiferromagnet--heavy-metal bilayers. show that drive much faster than ferromagnetic walls. As wall velocity approaches maximum spin-wave group velocity, undergoes Lorentz contraction and emits spin waves terahertz frequency range. The interplay between relativistic leads to efficient manipulation textures paves way for generation high signals from antiferromagnets.
Abstract Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such skins and health-monitoring devices. Although existing display high sensitivities, they can only be used specific purposes due to the narrow range of detectable (under tens kPa) difficulty forming highly integrated arrays. However, it is essential develop tactile wide in order use them diverse application areas including medical...
The orbital Hall effect describes the generation of current flowing in a perpendicular direction to an external electric field, analogous spin effect. As carries angular momentum as does, injection into ferromagnet can result torque on magnetization, which provides way detect With this motivation, we examine current-induced spin-orbit torques various ferromagnet/heavy metal bilayers by theory and experiment. Analysis magnetic reveals presence contribution from heavy metal, competes with In...
Spin Hall effect, an electric generation of spin current, allows for efficient control magnetization. Recent theory revealed that orbital effect creates which can be much larger than Hall-induced current. However, current cannot directly exert a torque on ferromagnet, requiring conversion process from to Here, we report two effective methods the through spin-orbit coupling engineering, us unambiguously demonstrate orbital-current-induced torque, or torque. We find is greatly enhanced by...
While it is often assumed that the orbital response suppressed and short ranged due to strong crystal field potential quenching, we show can be remarkably long in ferromagnets. In a bilayer consisting of nonmagnet ferromagnet, spin injection from interface results accumulation torque which rapidly oscillate decay by dephasing. contrast, even when an external electric applied only on nonmagnet, find substantially long-ranged induced angular momentum go far beyond dephasing length. This...
The phenomena based on spin-orbit interaction in heavy metal/ferromagnet/oxide structures have been investigated extensively due to their applicability the manipulation of magnetization direction via in-plane current. This implies existence an inverse effect, which conductivity such should depend orientation. In this work, we report a systematic study magnetoresistance (MR) W/CoFeB/MgO and its correlation with current-induced torque magnetization. We observe that MR is independent angle...
Spin-orbit coupling effect in structures with broken inversion symmetry, known as the Rashba effect, facilitates spin-orbit torques (SOTs) heavy metal/ferromagnet/oxide structures, along spin Hall effect. Electric-field control of is established for semiconductor interfaces, but it challenging involving metals owing to screening Here, we report that Pt/Co/AlOx laterally modulated by electric voltages, generating out-of-plane SOTs. This enables field-free switching perpendicular magnetization...
Abstract Current-induced spin torques enable the electrical control of magnetization with low energy consumption. Conventional magnetic random access memory (MRAM) devices rely on spin-transfer torque (STT), this however limits MRAM applications because nanoseconds incubation delay and associated endurance issues. A potential alternative to STT is spin-orbit (SOT). However, for practical, high-speed SOT devices, it must satisfy three conditions simultaneously, i.e., field-free switching at...
Abstract The utilization of ferromagnetic (FM) materials in thermoelectric devices allows one to have a simpler structure and/or independent control electric and thermal conductivities, which may further remove obstacles for this technology be realized. thermoelectricity FM/non-magnet (NM) heterostructures using an optical heating source is studied as function NM number multilayers. It observed that the overall signal those structures contributed by spin Seebeck effect anomalous Nernst (ANE)...
The magnetization direction in heavy-metal (HM)/ferromagnet bilayers can be electrically controlled by spin-orbit torque (SOT); however, the efficiency of SOT which depends on coupling HM layer or its spin-Hall angle has to improved further for actual applications. In this study, we report a significant enhancement effect Pt and resultant $\mathrm{Pt}/\mathrm{Co}/\mathrm{Al}{\mathrm{O}}_{x}$ structures controlling resistivity. We observed that effective increases about three times as...
Spin–orbit torque facilitates efficient magnetisation switching via an in-plane current in perpendicularly magnetised heavy-metal/ferromagnet heterostructures. The efficiency of spin–orbit-torque-induced is determined by the charge-to-spin conversion arising from either bulk or interfacial spin–orbit interactions both. Here, we demonstrate that and resultant Pt/CoFeB systems are significantly enhanced modification involving Ti insertion between Pt CoFeB layers. Spin pumping X-ray magnetic...
Spin-orbit torque (SOT) has been studied extensively in a heavy-metal (HM)/ferromagnet (FM) bilayer structure, where HM is an essential ingredient because spin current generated via the Hall effect within layer and/or Rashba-Edelstein from HM/FM interface. Here, we report observation of SOT ferrimagnetic $\mathrm{Tb}\text{\ensuremath{-}}\mathrm{Co}$ single with perpendicular magnetic anisotropy without layer. Using harmonic voltage measurements, investigate SOT-induced dampinglike effective...
The electrical control of antiferromagnetic moments is a key technological goal antiferromagnet-based spintronics, which promises favourable device characteristics such as ultrafast operation and high-density integration compared to conventional ferromagnet-based devices. To date, the manipulation by electric current has been demonstrated in epitaxial antiferromagnets with broken inversion symmetry or interfaced heavy metal, spin-orbit torque (SOT) drives domain wall. Here, we report...
Physical unclonable function (PUFs) utilize inherent random physical variations of solid-state devices and are a core ingredient hardware security primitives. PUFs promise more robust information than that provided by the conventional software-based approaches. While silicon- memristor-based advancing, their reliability scalability require further improvements. These currently limited output fluctuations associated additional peripherals. Here, highly reliable spintronic exploit field-free...
Spin Hall nano-oscillators (SHNOs) exploiting current-driven magnetization auto-oscillation have recently received much attention because of their potential for neuromorphic computing. Widespread applications devices with SHNOs require an energy-efficient method tuning oscillation frequency over broad ranges and storing trained frequencies in without the need additional memory circuitry. While voltage-driven has been demonstrated, it was volatile limited to megahertz ranges. Here, we show...
Magnetic random-access memory (MRAM), which stores information through control of the magnetization direction, offers promising features as a viable nonvolatile alternative, including high endurance and successful large-scale commercialization. Recently, MRAM applications have extended beyond traditional memories, finding utility in emerging computing architectures such in-memory probabilistic bits. In this work, we report highly reliable MRAM-based security devices, known physical...