Zintl phases, containing strongly covalently bonded frameworks with separate ionically bonded ions, have emerged as a critical materials family in which to couple magnetism and strong spin-orbit coupling to drive diverse topological phases of matter. Here we report the single-crystal synthesis, magnetic, thermodynamic, transport, and theoretical properties of the Zintl compound ${\mathrm{EuZn}}_2{\mathrm{P}}_2$ that crystallizes in the anti-${\mathrm{La}}_2{\mathrm{O}}_3$ (${\mathrm{CaAl}}_2{\mathrm{Si}}_2$) P-$3m1$ structure, containing triangular layers of ${\mathrm{Eu}}^{2+}$ ions. In-plane resistivity measurements reveal insulating behavior with an estimated activation energy of $E_g=0.11\mathrm{eV}$. Specific heat and magnetization measurements indicate antiferromagnetic ordering at $T_N=23\mathrm{K}$. Curie-Weiss analysis of in-plane and out of plane magnetic susceptibility from $T=150$ to 300 K yields $p_{\mathrm{eff}}=8.61$ for ${\mu }_{0}H\perp c$ and $p_{\mathrm{eff}}=7.74$ for ${\mu }_{0}H//c$, close to the expected values for the $4f^7 J=S=7/2 {\mathrm{Eu}}^{2+}$ ion and indicative of weak anisotropy. Below $T_N$, a significant anisotropy of ${\chi }_{\perp }/{\chi }_{//}\approx 2.3$ develops, consistent with $A$-type magnetic order as observed in isostructural analogs and as predicted by the density functional theory calculations reported herein. The positive Weiss temperatures of ${\theta }_W=19.2\mathrm{K}$ for ${\mu }_{0}H\perp c$ and ${\theta }_W=41.9\mathrm{K}$ for ${\mu }_{0}H//c$ show a similar anisotropy and suggest competing ferromagnetic and antiferromagnetic interactions. Comparing Eu magnetic ordering temperatures across trigonal $\mathrm{Eu}{M}_2{X}_2$ ($M=$ divalent metal, $X=$ pnictide) shows that ${\mathrm{EuZn}}_2{\mathrm{P}}_2$ exhibits the highest ordering temperature, with variations in $T_N$ correlating with changes in expected dipolar interaction strengths within and between layers and independent of the magnitude of electrical conductivity. These results provide experimental validation of the crystochemical intuition that the cation ${\mathrm{Eu}}^{2+}$ layers and the anionic ${\left(M_2{X}_2\right)}^{2–}$ framework can be treated as electronically distinct subunits, enabling further predictive materials design.

中文翻译：

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Zintl相绝缘体EuZn2P2中的A型反铁磁序

Zintl 相包含具有单独离子键合离子的强共价键合框架，已成为一种关键材料家族，其中耦合磁性和强自旋轨道耦合以驱动物质的不同拓扑相。在这里，我们报告了 Zintl 化合物的单晶合成、磁性、热力学、传输和理论性质${\mathrm{铕锌}}_2{\mathrm{磷}}_2$结晶在反${拉}_2{\mathrm{○}}_3$(${\mathrm{钙铝}}_2{硅}_2$) P-$3米1$结构，包含三角形层${\mathrm{欧盟}}^{2+}$离子。面内电阻率测量揭示了绝缘行为，估计活化能为${乙}_G=0.11\mathrm{电子伏特}$. 比热和磁化测量表明反铁磁排序在${吨}_{ñ}=23\mathrm{ķ}$. 面内和面外磁化率的居里-魏斯分析$吨=150$高达 300 K 的产量$p_{\mathrm{效果}}=8.61$为了${\mu }_{0}H\perp C$和$p_{\mathrm{效果}}=7.74$为了${\mu }_{0}H//C$，接近预期值$4F^7 Ĵ=\mathrm{小号}=7/2 {\mathrm{欧盟}}^{2+}$离子和表示弱各向异性。以下${吨}_{ñ}$，显着的各向异性${\chi }_{\perp }/{\chi }_{//}\approx 2.3$发展，与$\mathrm{一个}$如在同构类似物中观察到的并且如本文报道的密度泛函理论计算所预测的 - 型磁序。正韦斯温度${\theta }_W=19.2\mathrm{ķ}$为了${\mu }_{0}H\perp C$和${\theta }_W=41.9\mathrm{ķ}$为了${\mu }_{0}H//C$显示出类似的各向异性，并表明竞争的铁磁和反铁磁相互作用。比较三角范围内的 Eu 磁有序温度$\mathrm{欧盟}{米}_2{X}_2$($米=$二价金属，$X=$pnictide) 表明${\mathrm{铕锌}}_2{\mathrm{磷}}_2$表现出最高的订购温度，在变化${吨}_{ñ}$与层内和层间的预期偶极相互作用强度的变化相关，并且与电导率的大小无关。这些结果为阳离子的结晶化学直觉提供了实验验证。${\mathrm{欧盟}}^{2+}$层和阴离子${\left({米}_2{X}_2\right)}^{2–}$框架可以被视为电子上不同的子单元，从而实现进一步的预测材料设计。