Research Projects

Spintronics is an emerging technology that harnesses both the spin and charge of electrons, enabling faster, low-power, and non-volatile electronic devices. A key goal in this field is to efficiently generate spin currents and manipulate magnetization with minimal energy loss. In recent years, the integration of spintronics with topological quantum materials (TQMs) has opened exciting new possibilities for device innovation. TQMs such as Dirac and Weyl semimetals, topological insulators, 2D magnetic materials, and altermagnets, which exhibit unique quantum properties like spin-momentum locking and robust surface or bulk states. These features facilitate efficient spin generation and transport, often requiring lower switching currents and yielding high spin polarization. Topological semimetals (TSMs) have emerged as promising candidates owing to their large spin Hall conductivities, which stem from intrinsic Berry curvature effects in their band structures. However, a critical limitation in current spintronic technologies is the lack of suitable materials that can simultaneously support robust spin-polarized transport, strong spin-orbit interactions, and topological protection at room temperature. Recently, Heusler-type magnetic topological semimetal Co₂MnGa and other similar compounds such as Co₂Cr(Ga,Ge), Co₂Ti(Si,Ge,Sn), and Co₂MnAl which exhibit high anomalous Hall conductivity (AHC) due to nodal lines at the Fermi level that give rise to a large Berry curvature and anomalous Hall effect (AHE). Co₂MnGa has a ferromagnetic Curie temperature (TC) of 686 K, far above the room temperature, which provides practical device integration, while many TIs and magnetic topological materials, such as MnBi₂Te₄, require cryogenic temperatures to function. These advantages, along with the feasibility of thin-film synthesis and chemical tunability, render such Heusler compounds a promising materials platform for next-generation topological spintronics. Thin films often exhibit different electronic structures and disorder effects compared to their bulk analogs. Understanding the influence of structure, dimensionality, and disorder on magnetotransport phenomena in both bulk and thin films is therefore essential. This project is motivated by the potential of growing and engineering Co₂MnGa-type topological magnetic semimetals in bulk and thin-film form to serve as room-temperature, high-efficiency platforms for next-generation spintronic technologies. It focuses on the synthesis, structural and magnetic characterization, and detailed magnetotransport measurements, particularly targeting the anomalous Hall conductivity (AHC) and its decomposition into intrinsic (Berry curvature-driven) and extrinsic contributions. The research will build on recent theoretical and experimental insights, such as those in Co₂VAl and Co₂Cr(Ga,Ge), to examine how band topology, chemical substitution, and disorder affect AHE in these systems.