Considerable attention has been paid recently to $\mathrm{Fe}{\mathrm{Te}}_2{\mathrm{O}}_5\mathrm{Cl}$ due to reduced dimensionality and frustration in the magnetic subsystem, succession of phase transitions, and multiferroicity. The efforts to grow its selenite sibling resulted in the mixed halide compound $\mathrm{Fe}\left({\mathrm{Te}}_{1.5}{\mathrm{Se}}_{0.5}\right){\mathrm{O}}_5\mathrm{Cl}$, which was found crystallizing in a different structural type and possessing properties drastically different from those of a parent system. Its magnetic subsystem features weakly coupled ${\mathrm{Fe}}^{3+}-{\mathrm{Fe}}^{3+}$ dimers showing the regime of short-range correlations at $T_{\mathrm{M}}\sim 70\mathrm{K}$ and long-range order at $T_{\mathrm{N}}=22\mathrm{K}$. In a magnetically ordered state, sizable spin-orbital interactions lead to a small canting of ${\mathrm{Fe}}^{3+}$ moments. Magnetic dipole-dipole interactions contribute significantly to the experimentally observed orientation of magnetization easy axis in the $ac$ plane. The first principles calculations of leading exchange interactions were found in agreement with measurements of thermodynamic properties and Raman spectroscopy.

中文翻译：

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Fe（Te1.5Se0.5）O5Cl中的短程和长程磁序

最近已经引起了相当大的关注 $铁{特}_2{\mathrm{Ø}}_5氯$由于磁性子系统的尺寸减小和受挫，相变的连续性和多铁性。亚硒酸盐同胞生长的努力导致了混合卤化物的形成$铁（{特}_{1.5}{硒}_{0.5}）{\mathrm{Ø}}_5氯$，发现其结晶具有不同的结构类型，并且具有与父系统完全不同的特性。其磁子系统功能弱耦合${铁}^{3+}-{铁}^{3+}$ 二聚体显示短时相关机制 ${Ť}_{\mathrm{中号}}〜70\mathrm{ķ}$ 和远程订购 ${Ť}_{\mathrm{ñ}}=22\mathrm{ķ}$。在磁有序状态下，相当大的自旋轨道相互作用导致较小的倾斜${铁}^{3+}$片刻。磁偶极子-偶极子相互作用极大地促进了实验中观察到的易磁化轴的取向$\mathrm{一种}C$飞机。发现领先的交换相互作用的第一原理计算与热力学性质和拉曼光谱的测量相一致。