Ferromagnetism of Nanometer Thick Sputtered Fe3GeTe2 Films in the Absence of Two-Dimensional Crystalline Order: Implications for Spintronics Applications
Ferromagnetism of Nanometer Thick Sputtered Fe3GeTe2 Films in the Absence of Two-Dimensional Crystalline Order: Implications for Spintronics Applications
复制标题
DOI：
10.1021/acsanm.2c05213
复制
发表时间：
2023-02
影响因子：
5.9
通讯作者：
Qianwen Zhao;ChaoChao Xia;Han-tao Zhang;Baiqing Jiang;T. Xie;Kaihua Lou;C. Bi
中科院分区：
文献类型：
--
作者：
Qianwen Zhao;ChaoChao Xia;Han-tao Zhang;Baiqing Jiang;T. Xie;Kaihua Lou;C. Bi
二维单分子膜中铁磁性的发现激发了自旋电子学和材料科学的研究兴趣。然而，这些2D铁磁层主要是通过大规模制造和集成的不兼容方法制备的，此外，还没有探索所观察到的铁磁性是否与2D晶序实际相关的基本问题。在这里，我们选择了一个典型的二维铁磁材料，Fe3GeTe2，以解决这两个问题，通过研究其铁磁性在非晶态。采用磁控溅射法制备了厚度接近Fe_3GeTe_2单晶单层厚度极限（0.8nm）的非晶Fe_3GeTe_2薄膜。与结晶的Fe3GeTe2相比，我们发现基本的铁磁属性，如直接反映磁交换相互作用和局部各向异性能的居里温度，在非晶态中没有显著变化。这是由于短程原子顺序，证实了价态分析，是几乎相同的两个阶段。铁磁性的持久性在非晶对应物中也已被证实，通过磁阻测量，其中两个非常规的开关下降所产生的畴壁内的电输运清楚地观察到在非晶Fe3GeTe2单层。这些结果表明，结晶的Fe3GeTe2的长程铁磁顺序可能不相关的二维结晶顺序，和相应的铁磁属性可以利用在一个非晶态，适合大规模制造的半导体技术兼容的方式自旋电子学应用。
The discovery of ferromagnetism in two-dimensional (2D) monolayers has stimulated growing research interest in both spintronics and material science. However, these 2D ferromagnetic layers are mainly prepared through an incompatible approach for large-scale fabrication and integration, and moreover, a fundamental question of whether the observed ferromagnetism actually correlates with the 2D crystalline order has not been explored. Here, we choose a typical 2D ferromagnetic material, Fe3GeTe2, to address these two issues by investigating its ferromagnetism in an amorphous state. We have fabricated nanometer thick amorphous Fe3GeTe2films approaching the monolayer thickness limit of crystallized Fe3GeTe2(0.8 nm) through magnetron sputtering. Compared to crystallized Fe3GeTe2, we found that the basic ferromagnetic attributes, such as the Curie temperature which directly reflects magnetic exchange interactions and local anisotropic energy, do not change significantly in the amorphous states. This is attributed to the short-range atomic order, as confirmed by valence state analysis, being almost the same for both phases. The persistence of ferromagnetism in the ultrathin amorphous counterpart has also been confirmed through magnetoresistance measurements, where two unconventional switching dips arising from electrical transport within domain walls are clearly observed in the amorphous Fe3GeTe2single layer. These results indicate that the long-range ferromagnetic order of crystallized Fe3GeTe2may not correlate to the 2D crystalline order, and the corresponding ferromagnetic attributes can be utilized in an amorphous state which suits large-scale fabrication in a semiconductor technology-compatible manner for spintronics applications.