We report on the crystallographic information such as lattice parameters, atomic positions, bond lengths and angles, and local crystalline distortion size and mode of single-crystal YCrO3 compound by a high-resolution synchrotron X-ray diffraction study. The data was collected at 120 K (below TN∼ 141.5 K), 300 K (within [TN, TC]), and 500 K (above TC∼ 473 K). Taking advantages of high intensity and brilliance of synchrotron X-rays, we are able to refine collected patterns with the noncentrosymmetric monoclinic structural model (P1211, No. 4) that was proposed previously but detailed structural parameters have not determined yet. Meanwhile, we calculated patterns with the centrosymmetric orthorhombic space group (\emph{Pmnb}, No. 62) for a controlled study. Lattice constants \emph{a}, \emph{b}, and \emph{c} as well as unit-cell volume almost increase linearly upon warming. We observed more dispersive distributions of bond length and angle and local distortion strength with the P1211 space group. This indicates that (i) The local distortion mode of Cr2O6 at 120 K correlates the formation of the canted antiferromagnetic order by Cr1-Cr2 spin interactions mainly through intermediate of O3 and O4 ions. (ii) The strain-balanced Cr1-O3(O4) and Cr2-O5(O5) bonds as well as the local distortion modes of Cr1O6 and Cr2O6 octohedra at 300 K may be a microscopic origin of the previously-reported dielectric anomaly. Our study demonstrates that local crystalline distortion is a key factor for the formation of ferroelectric order and provides a complete set of crystallography for a full understanding of the interesting magnetic and quasi-ferroelectric properties of YCrO3 compound.
@article{arxiv.2112.02495,
title = {Insights into the structural symmetry of single-crystal YCrO$_3$ from synchrotron X-ray diffraction},
author = {Qian Zhao and Si Wu and Yinghao Zhu and Junchao Xia and Hai-Feng Li},
journal= {arXiv preprint arXiv:2112.02495},
year = {2024}
}