In spintronics, two-dimensional van der Waals crystals constitute a most promising material class for long-distance spin transport or effective spin manipulation at room temperature. To realize all-vdW-material-based spintronic devices, however, vdW materials with itinerant ferromagnetism at room temperature are needed for spin current generation and thereby serve as an effective spin source. We report theoretical design and experimental realization of a iron-based vdW material, Fe4GeTe2, showing a nearly room temperature ferromagnetic order, together with a large magnetization and high conductivity. These properties are well retained even in cleaved crystals down to seven layers, with notable improvement in perpendicular magnetic anisotropy. Our findings highlight Fe4GeTe2 and its nanometer-thick crystals as a promising candidate for spin source operation at nearly room temperature and hold promise to further increase T c in vdW ferromagnets by theory-guided material discovery.

中文翻译：

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富含磁性金属的范德华金属中的室温铁磁性。

在自旋电子学中，二维范德华晶体构成了在室温下进行长距离自旋传输或有效自旋操纵的最有前途的材料类别。然而，为了实现基于全vdW材料的自旋电子器件，自旋电流产生需要在室温下具有流动铁磁性的vdW材料，以用作自旋电流。我们报告了一种铁基vdW材料Fe4GeTe2的理论设计和实验实现，该材料显示出接近室温的铁磁有序，以及大的磁化强度和高电导率。这些特性甚至在低至7层的分裂晶体中也得到了很好的保留，垂直磁各向异性得到了显着改善。