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Magneto-optics induced by the spin chirality in itinerant ferromagnet Nd$_2$Mo$_2$O$_7$

I. Kézsmárki·S. Onoda·Y. Taguchi·T. Ogasawara·M. Matsubara·S. Iguchi·N. Hanasaki·N. Nagaosa·Y. Tokura
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Abstract

It is demonstrated both theoretically and experimentally that the spin chirality associated with a noncoplanar spin configuration produces a magneto-optical effect. Numerical study of the two-band Hubbard model on a triangle cluster shows that the optical Hall conductivity $σ_{xy}(ω)$ is proportional to the spin chirality. The detailed comparative experiments on pyrochlore-type molybdates $R_2$Mo$_2$O$_7$ with $R=$Nd (Ising-like moments) and $R=$Gd (Heisenberg-like ones) clearly distinguishes the two mechanisms, i.e., spin chirality and spin-orbit interactions. It is concluded that for $R$=Nd, $σ_{xy}(ω)$ is dominated by the spin chirality for the dc ($ω=0$) and the $d \to d$ incoherent intraband optical transitions between Mo atoms.

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I. Kézsmárki, S. Onoda, Y. Taguchi, T. Ogasawara, M. Matsubara, S. Iguchi, N. Hanasaki, N. Nagaosa, Y. Tokura. 2005-07-19. Magneto-optics induced by the spin chirality in itinerant ferromagnet Nd$_2$Mo$_2$O$_7$. https://doi.org/10.1103/physrevb.72.094427

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