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arXiv · 2407.01982

Atypical antiferromagnetic ordering in single crystalline quasi-2D honeycomb magnet YbI$_3$

Nashra Pistawala·Luminita Harnagea·Sitaram Ramakrishnan·Priyanshi Tiwari·M. P. Saravanan·Rajeev Rawat·Surjeet Singh
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Abstract

Here, we study YbI$_3$, a quasi-2D layered material with Yb atoms arranged on an ideal honeycomb network of edge-sharing YbI$_6$ octahedra, analogous to the low-temperature phase of $α-$RuCl$_3$. High quality single crystals of YbI$_3$ are grown from Yb and I as starting precursors, using the vapor transport technique. The grown crystals are characterized by single crystal x-ray diffraction, Raman spectroscopy, magnetization, and heat capacity probes. The crystal-field split ground state of Yb$^{3+}$ in \Yb~ is a well-isolated Kramers doublet with an effective moment $\rm J_{eff} = 1/2$. Upon cooling, the low-temperature heat capacity of \Yb~ reveals a broad peak at $\rm T_1 = 0.95$~K due to short-range ordering of the Yb moments, followed by a sharp peak at $\rm T_2 = T_N = 0.6$~K due to long-range ordering. The magnetic behavior is found to be weakly anisotropic with $χ^\parallel > χ^\perp$, where $χ^\parallel$ and $χ^\perp$ refers to the in-plane ($H \parallel ab$) and out-of-plane ($H \perp ab$) susceptibilities. The 2~K isothermal magnetization saturates at $\rm \approx~1.5~μ_B/Yb^{3+}$ (in-plane) and $\rm \approx~1~μ_B/Yb^{3+}$ (out-of-plane), suggesting the anisotropy to be easy-plane type. Low-temperature heat capacity, well below T$_N$, is found to vary as T$^α$ with $α~\approx~2.5$, indicating a possible unconventional magnetic ground state for YbI$_3$.

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Nashra Pistawala, Luminita Harnagea, Sitaram Ramakrishnan, Priyanshi Tiwari, M. P. Saravanan, Rajeev Rawat, Surjeet Singh. 2024-07-02. Atypical antiferromagnetic ordering in single crystalline quasi-2D honeycomb magnet YbI$_3$. https://arxiv.org/abs/2407.01982

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