Enhanced electrical magnetochiral effect by spin-hedgehog lattice structural transition

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 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), empirically known increase with $H$ paramagnetic fully ferromagnetic state lattice depend fluctuation properties helimagnetic state. We report here the eMChE over wide temperature range chiral-lattice magnet MnGe which spin hedgehog (HL) forms triple spin-helix modulation vectors. The magnitude nonreciprocal resistivity sharply enhanced course field-induced structural transition HL from cubic rhombohedral form. attributed asymmetric electron scatterings by vector chirality association large thermal fluctuations hedgehogs.