Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Department of Engineering, University of California, Berkeley, CA, 94720, USA.
Adv Mater. 2018 Jul;30(27):e1800199. doi: 10.1002/adma.201800199. Epub 2018 May 23.
Inversion symmetry breaking has become a vital research area in modern magnetism with phenomena including the Rashba effect, spin Hall effect, and the Dzyaloshinskii-Moriya interaction (DMI)-a vector spin exchange. The latter one may stabilize chiral spin textures with topologically nontrivial properties, such as Skyrmions. So far, chiral spin textures have mainly been studied in helimagnets and thin ferromagnets with heavy-element capping. Here, the concept of chirality driven by interfacial DMI is generalized to complex multicomponent systems and demonstrated on the example of chiral ferrimagnetism in amorphous GdCo films. Utilizing Lorentz microscopy and X-ray magnetic circular dichroism spectroscopy, and tailoring thickness, capping, and rare-earth composition, reveal that 2 nm thick GdCo films preserve ferrimagnetism and stabilize chiral domain walls. The type of chiral domain walls depends on the rare-earth composition/saturation magnetization, enabling a possible temperature control of the intrinsic properties of ferrimagnetic domain walls.
反转对称破缺已成为现代磁性研究的一个重要领域，其中包括拉什巴效应、自旋霍尔效应和 Dzyaloshinskii-Moriya 相互作用（DMI）——一种矢量自旋交换。后者可能稳定具有拓扑非平凡性质的手征自旋结构，如斯格明子。到目前为止，手征自旋结构主要在螺旋磁体和具有重元素覆盖层的薄铁磁体中进行研究。在这里，由界面 DMI 驱动的手征的概念被推广到复杂的多组分系统，并以非晶态 GdCo 薄膜中的手征亚铁磁为例进行了证明。利用洛伦兹显微镜和 X 射线磁圆二色性光谱，并通过厚度、覆盖层和稀土成分的剪裁，揭示了 2nm 厚的 GdCo 薄膜保留了亚铁磁性并稳定了手征畴壁。手征畴壁的类型取决于稀土成分/饱和磁化强度，从而有可能实现对亚铁磁畴壁固有特性的温度控制。
