Curvature-induced effects in magnetic nanostructures

具有手性磁性织构的手性相互作用材料是当前凝聚态研究的前沿。几何弯曲磁性薄膜中的曲率效应是实现手性磁性织构的一种可行的方法，传统的方法是基于材料的本征性质的调节。虽然有许多关于三维壳体中曲率诱导效应的理论预测，但在纳米磁学中交换和静磁驱动的新物理现象还没有得到实验探索。这主要是由于缺乏表征工具和制造方法，可以提供对低微米和亚微米尺度的复杂几何图形的访问，例如Tori、Möbius带材、球壳。在这个项目中，我们将讨论这些基本相关的方面。该项目的主要目标是联合三个实验小组和一个理论小组的努力，开发和探索制造低微米和亚微米级3D曲面磁壳的新方法。此外，我们还将从实验和理论两个方面对它们进行充分的表征，研究它们的复杂磁态和动力学。焦点将主要是以前没有实现的物体，包括但不限于环面、莫比乌斯带和球壳。关于它们的静态和动态特性，将使用广泛的实验技术来表征这些新的磁性结构。对于后者，将建立新的方法并应用于研究磁化动力学，例如从根本上吸引人的径向磁化瑞士辊。为了了解这些体系结构中的复杂磁结构，将使用基于有限元的微磁解算器进行高级微磁模拟，这些解算器通过图形卡的高并行计算能力进行加速。该项目不仅将加深我们对凝聚态中曲率诱导效应的理解，而且还将通过实验来检验新的理论概念和建议。这将为曲率效应如何用于未来实现新型3D设备提供更深入的洞察。

Materials with chiral interactions possessing chiral magnetic textures are at the forefront of current condensed matter research. Curvature effects in geometrically curved magnetic thin films emerged as a viable alternative to conventional approaches towards the realization of chiral magnetic textures, which are based on tuning of intrinsic properties of materials. Although there are numerous appealing theoretical predictions of curvature-induced effects in 3D shells, the novel physics of exchange- and magnetostatic-driven phenomena in nanomagnetism are not yet explored experimentally. This is mainly due to the lack of characterization tools and fabrication methods which can provide access to complex geometries at the low micrometer and sub-µm scale, e.g. tori, Möbius strips, spherical shells. In this project we address these fundamentally relevant aspects. The main objective of this project is to join efforts of three experimental groups and one theory group to develop and exploit novel routes in fabrication of 3D curved magnetic shells at the low micrometer and sub-µm scale. In addition, we will fully characterize them and study their complex magnetic states and their dynamics both, experimentally and theoretically. In the focus will be mainly objects which were not realized before, including but not limited to torus, Möbius strip, and spherical shell. These new magnetic architectures will be characterized using a broad range of experimental techniques with respect to their static and dynamic properties. For the latter, new methods will be established and applied to study magnetization dynamics, e.g. in fundamentally appealing radially magnetized Swiss rolls. To understand complex magnetic structures in these architectures, advanced micromagnetic simulations will be carried out using finite element based micromagnetic solvers which are accelerated by the high parallel computing power of graphics cards. This project will not only deepen our understanding on curvature-induced effects in condensed matter but also will put novel theoretical concepts and proposals to the test by experiment. This will provide deepened insight into how curvature effects can be used for future realization of novel 3D devices.