Antiferromagnetic resonance in $\hat{I}\pm$-MnTe

Abstract

Antiferromagnetic resonance in a bulk $\hat{I}\pm$-MnTe crystal is investigated using both frequency-domain and time-domain THz spectroscopy techniques. At low temperatures, an excitation at the photon energy of $(3.5\pm 0.1)$~meV is observed and identified as a magnon mode through its distinctive dependence on temperature and magnetic field. This behavior is reproduced using a simplified model for antiferromagnetic resonance in an easy-plane antiferromagnet. The results of our experiments, when compared to exchange constants established in the literature, allow us to extract the out-of-plane component of the single-ion magnetic anisotropy reaching $(40\pm 10)$~$\hat{I}¼$eV.

12 pages, 7 figures