Modified anisotropy and distinct phase diagrams in the nearly isotropic $S=1$ triangular-lattice antiferromagnet $\mathrm{Rb_2Ni(SeO_3)_2}$
Year: 2026
Type: preprint
Abstract: The triangular-lattice antiferromagnet serves as a benchmark platform for realizing exotic quantum phases, in which magnetic anisotropy plays an essential role. In this work, we report modified magnetic anisotropy and phase diagrams in the nearly isotropic $S=1$ triangular-lattice antiferromagnet $\mathrm{Rb_2Ni(SeO_3)_2}$, compared with those of its isostructural analog $\mathrm{K_2Ni(SeO_3)_2}$. The magnetic susceptibility of $\mathrm{Rb_2Ni(SeO_3)_2}$ exhibits an easy-axis anisotropy with $g_c > g_{ab}$, opposite to the easy-plane anisotropy observed in $\mathrm{K_2Ni(SeO_3)_2}$. The single Néel transition observed at zero field splits into two transitions at around 10~T, and a magnetization plateau is observed between 21~T and 37~T for both out-of-plane ($H\parallel c$) and in-plane ($H\parallel ab$) field directions in $\mathrm{Rb_2Ni(SeO_3)_2}$. We construct magnetic phase diagrams that are distinct between $\mathrm{Rb_2Ni(SeO_3)_2}$ and $\mathrm{K_2Ni(SeO_3)_2}$. These findings highlight the sensitivity of field-induced magnetic phase behavior to anisotropy in nearly isotropic triangular-lattice antiferromagnets.
Source: arXiv (Cornell University)
Institutions: Renmin University of China, Chinese Academy of Sciences, Hefei Institutes of Physical Science, High Magnetic Field Laboratory, The Institute for Solid State Physics, The University of Tokyo, Southern University of Science and Technology, Great Bay University, École Polytechnique Fédérale de Lausanne
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7222573532