Research Projects

This project aims to develop a new class of magnetic tunnel junctions (MTJs) that incorporate skyrmions, a topologically stable, nanoscale spin structures, to achieve high-density, low-power spintronic memory devices. Skyrmions are uniquely suited for this purpose due to their robust stability, minimal energy requirements for manipulation, and scalability. Traditional MTJ-based memory, such as magnetic random-access memory (MRAM), currently faces challenges in energy efficiency and scalability because it relies on spin-transfer torque (STT) switching, which demands high current densities. This research proposes to overcome these limitations by harnessing spin-orbit torques (SOTs) to create and manipulate skyrmions in MTJs. The main objective is to establish functional skyrmion-based MTJs (S-MTJs) by stabilizing skyrmions within the MTJ free layer and achieving a reliable readout through tunneling magnetoresistance (TMR). This goal requires the optimization of materials for stable skyrmion formation and efficient SOT generation, as well as demonstrating repeatable skyrmion nucleation, manipulation, and detection within the MTJ structure. The hypothesis underlying this work is that optimized heavy metal (HM) and ferromagnet (FM) multilayers, potentially with light metal (LM) capping layers, will enable room-temperature skyrmion stability, which can then be electrically read and manipulated within an MTJ device. To achieve these objectives, a range of advanced experimental techniques will be used. Materials synthesis will focus on developing HM|FM multilayers with strong interfacial DMI to support skyrmion formation. The SOTs will be optimized through 2nd harmonic Hall measurements in HM|FM|LM heterostructures to maximize efficiency. Following this, MTJ nanopillars (~100 nm in size) will be fabricated with precise patterning through electron-beam lithography, while deposition methods will ensure interface sharpness to support efficient skyrmion behaviour and stability. Finally, controlled skyrmion nucleation will be achieved using current pulses, and the TMR response will allow for accurate skyrmion detection. The anticipated impact of this work is substantial for both fundamental and applied research in spintronics. Integrating skyrmions into MTJs will advance energy-efficient memory technology beyond current MRAM capabilities, offering both higher performance and density. This project will establish an in-operando magnetic force microscopy (MFM) technique with electrical measurements to directly correlate electrical signals with skyrmionic spin textures. As a first in India, this powerful tool will enable simultaneous detection of electrical signals and magnetic states, opening significant opportunities for advanced spintronics research and the development of next-generation memory and logic devices.