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We are an experimental research group focused on exploring advanced magnetic materials, spin–orbit torque (SOT) devices, and novel two-dimensional (2D) systems. Our ultimate goal is to develop SOT-MRAM and probabilistic bits for neuromorphic computing, paving the way for energy-efficient, reconfigurable, and intelligent hardware systems.
Our work integrates cutting-edge materials synthesis, nanoscale device fabrication, and precision magnetic characterization, combining fundamental insights with application-driven innovation.
Our research spans three major thrust areas at the intersection of magnetism, spintronics, and advanced materials.
- Spin–Orbit Torque Devices and Multistate Memory
A central theme in spintronics is the inter-conversion of charge and spin currents. Recently, a focus has been on magnetic insulators where spin transport occurs through spin-wave propagation and spin currents can be generated by either spin injection or thermal gradients. These phenomena can be studied in simple bilayer films consisting of a ferrimagnetic (FIM) or Antiferromagnetic (AFM) insulator, and a heavy metal (HM) with large spin-orbit coupling such as Pt,W and so on. Spin to charge current conversion in such bilayers occurs by the inverse spin-Hall and Rashba-Edelstein effects.
Spin to charge conversion enables determination of the spin Seebeck effect (SSE). A thermal gradient across the FIM film produces a spin current into a neighboring heavy metal film, resulting in a transverse charge current or a voltage across the heavy metal film in an open circuit situation. Recent studies have demonstrated significant torques associated with thermally generated spin currents in magnetic tunnel junctions. Thermal gradients, thus, provide a convenient route to characterize the spin transport as well as a means to study the inverse effects, such as the spin torque on the AFM/ FIM magnetization in response to spin currents associated with charge current flow in the HM.
Schematic diagram of SOC and SOT phenomenon: (a) A three-dimensional representation of SOT, (b) Schematic diagram of spin Hall effect, (c) Rashba–Edelstein effect with an internal electric field ER perpendicular to the film plane, (d) SOT effect with field like and damping like torque.
In SMDL lab, we design spin–orbit torque (SOT)-driven devices to enable reconfigurable memory and neuromorphic logic. By combining SOT with magnetic fields, we achieve multistate memristive behavior, advancing beyond binary switching. Our work also surveys the potential of 2D van der Waals materials to enhance SOT effects for ultralow-power spintronic applications.
Emergence of considerable thermoelectric effect due to the addition of an underlayer in Pt/Co/Pt stack
Pt/Co/NiFe/Pt stack with the experimental geometries and SOT directions.
Initialization-free multistate memristor: Synergy of spin–orbit torque and magnetic fields
2. Unconventional Torque in 2D Materials
2. Unconventional Torque in 2D Materials
We are actively investigating unconventional torque mechanisms arising from Berry curvature, topological effects, and nonlinear Hall phenomena in 2D materials and heterostructures. This work aims to unlock new pathways for achieving field-free switching, probabilistic bit behavior, and next-generation neuromorphic architectures.
Typical 2D device.
3. Magnetic Nanostructures and Advanced Magnetic Characterization
3. Magnetic Nanostructures and Advanced Magnetic Characterization
We investigate the magnetic states and switching behaviors in nanoscale systems like nanotubes and multilayer films, using advanced techniques such as remanent ferromagnetic resonance and planar Hall measurements. These studies reveal hidden magnetic configurations and enable new device functionalities.
Comparison of experimentally obtained M-H measurement and simulated M-H for nanotubes.
Variation of the FMR absorption with frequency at remanent field (RFMR)
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