The University of Tokyo · Physics and Astronomy
Professor Aki Kitaori's research lab specializes in quantum spintronics and emergent electromagnetic phenomena in quantum materials, with a focus on helimagnetic and chiral systems. The lab investigates current-driven spin dynamics, emergent electromagnetic induction (EEMI), and nonreciprocal transport effects such as the electrical magnetochiral effect, aiming to develop nanoscale inductor elements for next-generation electronics. Using advanced techniques like small-angle neutron scattering and single-crystal growth, the group explores the interplay between spin textures, lattice chirality, and electronic responses in materials like YMn₆Sn₆ and Tb₅Sb₃, targeting room-temperature operation and quantum-scale device integration. Their work bridges fundamental quantum phenomena with practical applications in miniaturized electronic components.
Figures are computed from collected data and may differ slightly.
Emergent electromagnetic induction based on electrodynamics of noncollinear spin states may enable dramatic miniaturization of inductor elements widely used in electric circuits, yet the research is still in its infancy and many issues must be resolved toward its application. One such problem is how to increase working temperature to room temperature, and possible thermal agitation effects on the quantum process of the emergent induction are unknown. We report here large emergent electromagnetic
Ac current-driven motions of spiral spin textures can give rise to emergent electric fields acting on conduction electrons. This in turn leads to the emergent electromagnetic induction effect which may realize quantum inductor elements of micrometer size. ${\mathrm{YMn}}_{6}{\mathrm{Sn}}_{6}$ is a helimagnet with a short helical period (2--3 nm) that shows this type of emergent inductance beyond room temperature. To identify the optimized materials conditions for ${\mathrm{YMn}}_{6}{\mathrm{Sn}}
In helimagnetic metals, ac current-driven spin motions can generate emergent electric fields acting on conduction electrons, leading to emergent electromagnetic induction (EEMI). Recent experiments reveal the EEMI signal generally shows a strongly current-nonlinear response. In this study, we investigate the EEMI of Tb<sub>5</sub>Sb<sub>3</sub>, a short-period helimagnet. Using small angle neutron scattering we show that Tb<sub>5</sub>Sb<sub>3</sub> hosts highly disordered helimagnetism with a d
Nonreciprocal resistance, depending on both directions of current $\mathbit{j}$ and magnetic-field $\mathbit{H}$ or magnetization $\mathbit{M}$, is generally expected to emerge in a chiral conductor and be maximized for $\mathbit{j}\phantom{\rule{4pt}{0ex}}\ensuremath{\parallel}\phantom{\rule{4pt}{0ex}}\mathbit{H}(\mathbit{M}$). This phenomenon, electrical magnetochiral effect (eMChE), is empirically known to increase with $H$ in a paramagnetic or fully ferromagnetic state on chiral lattice or t
We have successfully grown single crystalline Tb5Sb3 with the hexagonal structure, which was reported to exhibit successive transitions among complex spiral magnetic structures with changing temperature. Through the measurements of specific heat and magnetization of the single crystalline Tb5Sb3, we have identified only one clear magnetic transition at 133 K. The ordered moments are approximately oriented in the hexagonal basal plane, while the hard axis of magnetization corresponds to the [0001
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