Research Projects

Magnetic skyrmions are topologically-protected whirlpool-like spin configurations that are stabilized in a variety of magnets. In 2008, Parkin introduced the concept of racetrack memories, in which data encoded as ferromagnetic domains walls are moved through an electric current. It was later realized that the efficiency of this idea is much increased by substituting magnetic skyrmions for domain walls, since skyrmions can be controlled with electric currents up to five orders of magnitude lower than that needed for domain wall motion. In order to turn these skyrmion-based racetrack devices into reality, it is crucial to identify materials that host these magnetic skyrmions near room temperature. Furthermore, for the development of ultra-high density data storage devices, these magnetic skyrmions are required to be very small, just a few nanometers in size. Although many skyrmion-hosting compounds have been discovered, their practical applications are hindered by fundamental constraints. For instance, skyrmions in chiral magnets are either stable at cryogenic temperatures or too large for high-density storage applications. Therefore, it is essential to widen the present landscape of the skyrmion hosting compounds by identifying novel systems, that can host small-sized skyrmions near the room temperature. This can help close the gap between fundamental science and practical applications. The goal of this project is to explore potential materials that could host skyrmions, including both theoretically anticipated candidates and well-established systems, where the magnetic interactions that stabilize skyrmions can be systematically adjusted through structural engineering and chemical substitution. Such tuning of the magnetic interactions, can alter the skyrmion phase stability, temperature range as well as the skyrmion size, thereby, providing a pathway to overcome the drawbacks of technological limitations. We plan to synthesize and investigate the following systems: a) B20 chiral magnets: Fe1-xCoxGe and FeGe1-xSix b) 4d or 5d doped B20 chiral magnets: CoSi and FeSi compounds doped with Ir, Ru and Os. c) β-Mn type CoxZnyMnz (x+y+z=20) chiral magnets doped with Fe or Ru d) Other potential skyrmion hosts: Cr1-xMnxGe, Gd2Ir0.97Si3 and Mn2Pd0.5Ir0.5Sn. The synthesized samples will undergo extensive characterization through DC and AC susceptibilities, magneto-transport and magneto-heat capacity measurements. These measurements are crucial for the detection of the skyrmion phase as well as the shrinkage in skyrmion size. In addition, relaxation dynamic study through AC susceptibility will help offer insights into the stability and robustness of the skyrmion phase making it possible to evaluate their feasibility for technological applications. Real and reciprocal space imaging techniques such as magnetic force microscopy (MFM) and small angle neutron scattering (SANS) will be used to directly visualize the skyrmion lattice of these compounds.