Research Projects

The emergence of topological spin states, such as skyrmions, has revolutionized the field of condensed matter physics, offering a promising platform for next-generation spintronic devices characterized by low power consumption, enhanced data density, and topological protection against perturbations. Despite progress in chiral magnets, finding topological spin states in centrosymmetric lattices remains a research frontier. The discovery of a field-induced skyrmion lattice (SkL) in Gd₂PdSi₃ [T. Kurumaji et al., Sci. 365, 914 (2019)], Gd₃Ru₄Al₁₂ [M. Hirschberger et al., Nat. Commun. 10, 5831 (2019)] and GdRu₂Si₂ [N. D. Khanh et al., Nat. Nanotechnol. 15, 444 (2020)] shows centrosymmetric structures can stabilize skyrmion phases, even in the absence of Dzyaloshinskii-Moriya interaction (DMI), primarily via geometrical frustrations, Ruderman-Kittel-Kasuya-Yosida exchange and itinerant electrons mediated exchanges. Gd2PdSi3, one of the SkL hosts, adopts a centrosymmetric AlB₂ derived P6/mmm structure, suppressing DMI yet enabling nanometric skyrmion, which give rise to a giant topological Hall effect and strong device potential. Here we propose to investigate the RAlGa (R = Y, La-Lu) intermetallic, which also adopt a hexagonal AlB₂-type structure, making them excellent candidates for hosting topological spin states in a controlled and tunable manner. Preliminary reports indicate that the RAlGa compounds exhibit a rich variety of magnetic behaviors, including strong magnetic anisotropy, metamagnetic transitions (MMTs), and noncollinear magnetic orders- all hallmarks of frustrated magnetism. For example, PrAlGa shows weak in-plane anisotropy enabling smooth MMTs along certain directions [120] and [100] [A. Garnier et al., JMMM 167, 52 (1997)], while DyAlGa [D. Gignoux et al., J. Alloys Compd. 326, 143 (2001)] and HoAlGa [D. Gignoux et al., JMMM 98, 333 (1991)] display multiple MMTs along [001], indicating complex magnetic phase diagrams sensitive to external fields and composition. Additionally, subtle compositional tuning of Al and Ga ratios or replacing Ga with Si introduces structural distortions that can modify the symmetry and electronic environment, potentially stabilizing exotic spin textures. Our research aims to systematically explore the magnetic, transport, and topological properties of RAlGa compounds across the rare-earth series, with particular emphasis on identifying and stabilizing nontrivial spin textures under accessible magnetic fields and temperatures. By integrating experimental techniques such as single-crystal growth, x-ray diffraction, magnetometry, magnetotransport, and neutron scattering with theoretical modeling, we aim to construct a comprehensive understanding of the mechanisms governing the emergence of topological spin states in these materials. In summary, investigating RAlGa compounds offers a compelling and timely opportunity to study non-trivial spin textures with strong scientific and technological potential.