Thickness-dependent and strain-tunable magnetism in two-dimensional van der Waals VSe2
Thickness-dependent and strain-tunable magnetism in two-dimensional van der Waals VSe2
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DOI：
10.1007/s12274-022-4400-9
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发表时间：
2022-05
期刊：
影响因子：
9.9
通讯作者：
Wenjuan Ci;Huali Yang;Wuhong Xue;Ruilong Yang;Baohua Lv;Peng Wang;Run-Wei Li;Xiaohong Xu
中科院分区：
文献类型：
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作者：
Wenjuan Ci;Huali Yang;Wuhong Xue;Ruilong Yang;Baohua Lv;Peng Wang;Run-Wei Li;Xiaohong Xu
具有降低维数的二维（2D）货车德瓦耳斯（vdW）磁性材料与它们的块体对应物相比通常表现出意想不到的性质。特别地，2D结构的机械柔性、在减小的层厚度下增强的铁磁性以及稳健的垂直磁各向异性对于构造新型自旋电子器件是相当有吸引力的。VdW二硒化钒（VSe 2）是一种有吸引力的材料，其本体是顺磁性的，而单层是铁磁性的，居里温度（Tc）高于室温。为了探索其可能的器件应用，VSe 2的厚度依赖的磁性和应变调制行为的详细调查是非常必要的。本文采用化学气相沉积（CVD）法可控制备VSe 2纳米片。在室温下，发现少层单层VSe 2纳米片表现出磁畴结构。环境磁力显微镜（MFM）相位图像揭示了一个清晰的厚度依赖性的磁性和MFM相衬是可追溯的层厚度低于106 nm的纳米片。此外，施加应变被发现有效地调制磁矩和矫顽场的2D VSe 2在室温下。这些结果对于理解高温二维磁体的铁磁性以及构造新型的应变电子器件或柔性自旋电子器件具有重要意义。
Two-dimensional (2D) van der Waals (vdW) magnetic materials with reduced dimensionality often exhibit unexpected properties compared to their bulk counterparts. In particular, the mechanical flexibility of 2D structure, enhanced ferromagnetism at reduced layer thickness, as well as robust perpendicular magnetic anisotropy are quite appealing for constructing novel spintronic devices. The vdW vanadium diselenide (VSe2) is an attractive material whose bulk is paramagnetic while monolayer is ferromagnetic with a Curie temperature (Tc) above room temperature. To explore its possible device applications, a detailed investigation on the thickness-dependent magnetism and strain modulation behavior of VSe2is highly demanded. In this article, the VSe2nanoflakes were controllably prepared via chemical vapor deposition (CVD) method. The few-layer single VSe2nanoflakes were found to exhibit magnetic domain structures at room temperature. Ambient magnetic force microscopy (MFM) phase images reveal a clear thickness-dependent magnetism and the MFM phase contrast is traceable for the nanoflakes of layer thickness below ∼ 6 nm. Moreover, applying strain is found efficient in modulating the magnetic moment and coercive field of 2D VSe2at room temperature. These results are helpful for understanding the ferromagnetism of high temperature 2D magnets and for constructing novel straintronic devices or flexible spintronic devices.