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arXiv · 1906.12327

Lattice and magnetic dynamics in polar chiral incommensurate antiferromagnet Ni$_2$InSbO$_6$

M. A. Prosnikov·A. N. Smirnov·V. Yu. Davydov·Y. Araki·T. Arima·R. V. Pisarev
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Abstract

Complex systems with coexisting polarity, chirality and incommensurate magnetism are of great interest because they open new degrees of freedom in interaction between different subsystems and therefore they host a plethora of intriguing physical properties. Here we report on optical properties and lattice and spin dynamics of Ni$_2$InSbO$_6$ single crystals studied with the use of polarized optical microscopy and micro-Raman spectroscopy in the temperature range 10-300 K. Ni$_2$InSbO$_6$ crystallizes in a polar structure described by the noncentrosymmetric space group R3 and two types of structural domains were visualized due to natural optical activity of opposite chirality. Raman tensor elements of most A and E phonons along with their symmetry were determined. The manifestation of LO-TO splitting was observed for the A modes. By tracking the temperature dependencies of phonon frequencies the well pronounced spin-phonon interaction was observed for several modes below and above the Néel transition temperature TN = 76 K. In antiferromagnetic phase a wide excitation centred at 247 cm-1 was detected and assigned to the two-magnon mode and this value was used for estimating exchange parameters through linear spin-wave theory calculations.

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M. A. Prosnikov, A. N. Smirnov, V. Yu. Davydov, Y. Araki, T. Arima, R. V. Pisarev. 2019-06-28. Lattice and magnetic dynamics in polar chiral incommensurate antiferromagnet Ni$_2$InSbO$_6$. https://doi.org/10.1103/physrevb.100.144417

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