Doping control of magnetism and emergent electromagnetic induction in high-temperature helimagnets

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. YMn6Sn6 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 YMn6Sn6-type room-temperature emergent inductors, we have investigated emergent electromagnetic inductance (EEMI) as the magnetism is modified through systematic partial substitution of Y by Tb. By small angle neutron scattering and inductance measurements, we have revealed that the pinning effect on the spin-helix translational mode by Tb doping selectively and largely suppresses the negative component of EEMI, while sustaining the positive inductance arising from the spin tilting mode. We also find that, in addition to the spin helix, even the spin-collinear antiferromagnetic structure can host the positive EEMI due to thermally enhanced spin fluctuations. The present study highlights the facile control of both the magnitude and sign of EEMI beyond room temperature and thus suggests a route to expand the range of emergent inductor candidate materials.

Automated summary

AC current-driven motions of spiral spin textures can create new electric fields and induce emergent electromagnetic induction effect, potentially realizing quantum inductor elements of micrometer size. Research on YMn6Sn6 helimagnet reveals the optimized conditions for emergent inductors beyond room temperature, achieved by modifying the magnetism through partial substitution of Y by Tb. The study demonstrates the control of both magnitude and sign of emergent electromagnetic inductance, and expands the range of potential candidate materials for emergent inductors.