AI 中文总结
研究发现绝缘亚铁磁体Eu$_2$MnSi$_2$O$_7$的临界行为由长程偶极相互作用支配，其临界指数接近平均场值，该材料为探索亚铁磁性和长程相互作用提供了新平台。
AI 中文摘要
我们报道了Eu$_2$MnSi$_2$O$_7$中的平均场临界行为，该化合物是一种硅镁石型亚铁磁体，具有仅由自旋贡献的Eu$^{2+}$和Mn$^{2+}$磁矩，轨道贡献可忽略不计。磁化测量结合中子粉末衍射显示，其临界指数接近平均场值，表明在该绝缘亚铁磁体中，长程偶极相互作用支配着渐近临界行为。经精修的磁结构由磁空间群$P2_12_1^\fprime2^\fprime$描述，呈现由Dzyaloshinskii-Moriya相互作用驱动的倾斜亚铁磁构型，反映了晶格的非中心对称特性。这些结果将平均场理论的适用性扩展到复杂绝缘磁体，并确立Eu$_2$MnSi$_2$O$_7$作为探索亚铁磁性和长程相互作用的平台。据我们所知，这是首例由偶极相互作用驱动平均场临界性的绝缘亚铁磁体。
英文摘要
We report mean-field critical behavior in Eu$_2$MnSi$_2$O$_7$, a melilite-type ferrimagnet with spin-only Eu$^{2+}$ and Mn$^{2+}$ moments and negligible orbital contributions. Magnetization measurements combined with neutron powder diffraction reveal critical exponents close to the mean-field values, indicating that long-range dipolar interactions govern the asymptotic critical behavior in this insulating ferrimagnet. The refined magnetic structure, described by the magnetic space group $P2_12_1^\prime2^\prime$, exhibits a tilted ferrimagnetic configuration driven by the Dzyaloshinskii-Moriya interaction, reflecting the noncentrosymmetric nature of the lattice. These results extend the applicability of mean-field theory to complex insulating magnets and establish Eu$_2$MnSi$_2$O$_7$ as a platform for exploring ferrimagnetism and long-range interactions. To our knowledge, this is the first insulating ferrimagnet in which dipolar interactions drive mean-field criticality.
Comments8 pages, 4 figures
Journal refPhysical Review Letters 137, 076703 (2026)
