Figure 1

Power transmission spectra of ${\mathrm{HoMnO}}_3$ with polarized far-IR light incident along the crystal’s [110] direction at $T=10\mathrm{K}$. Arrows indicate magnetic absorption lines. The dotted line illustrates the simulation of the transmission spectrum using Eqs. (1, 2) and the parameters ${ϵ}_0=9.07$, $\sigma =0.9{\mathrm{cm}}^{-1}$, with magnetic resonances centered at 27.5, 43.5, and $52.1{\mathrm{cm}}^{-1}$.Reuse & Permissions

Figure 2

Transmission maps for the ($h\perp c$) polarization where darker color indicates lower transmission. Left panel—static field $B\parallel c$, right panel—$B\perp c$. The bars above the panels set the absolute transmission scale. Symbols represent magnetic resonance positions extracted from fitting the measured transmission using Eqs. (1, 2). Resonances are labeled by the same numbers used in Fig. 1. The inset of the left panel is a scheme of the transition 2, which happens from the ground state (GS) doublet. The final state of the transition is assumed to be a singlet. In low magnetic field, the GS doublet splits and two resonance lines are observed as illustrated by the two vertical arrows on the left. In high magnetic field, the splitting of the GS becomes large enough for a thermal depopulation of the upper branch. Only one resonance line is observed, as the single vertical arrow on the right illustrates.Reuse & Permissions

Figure 3

Field dependence of triangular AFMR frequencies at $T=10\mathrm{K}$. The measured splitting of the resonance by magnetic field is about twice the splitting calculated using the free energy of Eq. (3).Reuse & Permissions