Abusa Yao, Viswanathan Gayatri, Obeng John, Opare-Addo Jemima, Ross Emma, Oppong Richeal, Ojo Iyanu, Kumar Ajay, Smith Emily, Rosenthal Joel, Mudryk Yaroslav, Lebedev Oleg I, Kovnir Kirill
Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.
Ames National Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States.
J Am Chem Soc. 2025 Aug 28. doi: 10.1021/jacs.5c11147.
Two-dimensional (2D) magnetic materials with exotic magnetic properties have garnered significant interest due to their potential applications in spintronics and data storage technologies. However, the limited availability of intrinsic 2D magnetic materials has driven efforts to induce and manipulate magnetism in otherwise nonmagnetic 2D systems through approaches such as chemical intercalation, defect engineering, and substitutional doping. Herein, we present a facile, method for incorporating 3 transition metals (Cr, Co, and Ni) into the nonmagnetic PtSe sublattice. This synthetic approach enables control over layer thickness of PtSe ( = Cr, Co, Ni) nanosheets by varying the identity and annealing conditions. Comprehensive scattering and spectroscopic characterizations confirm the successful and homogeneous substitution of atoms at the Pt site, rather than intercalation, and reveal a strong correlation between nanosheet thickness and the identity of the substituting metal. High-temperature annealing of the nanosheets promotes an irreversible transformation toward the bulk phase, allowing for detailed characterization of structural and magnetic properties. A case study of PtCrSe reveals that nanosheet thickness plays a critical role in modulating local magnetic interactions. While Cr atoms in the as-synthesized few-layers-thick nanosheets exhibit predominantly short-range antiferromagnetic interactions, the emergence of short-range ferromagnetic exchange is revealed in the bulk material. Detailed susceptibility and remanent magnetization measurements further demonstrate that bulk PtCrSe adopts a frustrated magnetic ground state with clear signatures of ferromagnetic cluster-glass behavior. The systematic investigation presented herein establishes a clear and robust protocol for the synthesis and in-depth characterization of 2D transition-metal-substituted PtSe materials with varying layer thickness and paves a path toward their realization in spintronic and magnetic device applications.
具有奇异磁性能的二维（2D）磁性材料因其在自旋电子学和数据存储技术中的潜在应用而备受关注。然而，本征二维磁性材料的有限可用性促使人们通过化学插层、缺陷工程和替代掺杂等方法，在原本非磁性的二维体系中诱导和操纵磁性。在此，我们提出了一种简便的方法，将3种过渡金属（Cr、Co和Ni）掺入非磁性的PtSe亚晶格中。这种合成方法能够通过改变金属种类和退火条件来控制PtSe（ = Cr、Co、Ni）纳米片的层厚。综合散射和光谱表征证实了在Pt位点成功且均匀地发生了原子替代而非插层，并揭示了纳米片厚度与替代金属种类之间的强相关性。纳米片的高温退火促进了向体相的不可逆转变，从而能够详细表征其结构和磁性。以PtCrSe为例，研究表明纳米片厚度在调节局部磁相互作用中起着关键作用。在合成的几层厚纳米片中，Cr原子主要表现出短程反铁磁相互作用，而在体材料中则出现了短程铁磁交换。详细的磁化率和剩余磁化强度测量进一步表明，体相PtCrSe呈现出具有明显铁磁团簇玻璃行为特征的受挫磁基态。本文所进行的系统研究为合成和深入表征具有不同层厚的二维过渡金属替代PtSe材料建立了清晰且可靠的方案，并为其在自旋电子学和磁性器件应用中的实现铺平了道路。
