Peculiarities of optical absorption spectra of NdFe$_3$(BO$_3$)$_4$ crystal in magnetically ordered state and at the transition to spiral magnetic phase
V. V. Slavin, I. S. Kachur, V. S. Kurnosov, V. G. Piryatinskaya
Published: 2025/9/18
Abstract
We study experimentally and theoretically optical absorption spectra of neodymium ferroborate in the temperature range $6-32$ K. We show that the temperature dependences of integral intensities of absorption lines demonstrate qualitatively different behavior for $\sigma$- and $\pi$-polarizations of the light. We suggest that this behavior may be caused by the appearance of a spiral magnetic structure in the compound under study. To describe the temperature dependences of lines intensities we propose a theoretical model which takes into account the Dzyaloshinskii-Moriya interaction between Nd$^{3+}$ and Fe$^{3+}$ ions.