Spin dynamics in laterally patterned magnetic landscapes with ferromagnetic/paramagnetic interfaces

由于过渡金属合金的磁性能对结构失序非常敏感，因此为制备横向磁性纳米结构提供了独特的机会。这种具有相邻铁磁区（FM）和顺磁区（PM）周期性分布的人工磁景观有望用于纳米尺度自旋相关现象的开发。它们可以用Fe60Al40合金的离子束辐照产生。该材料在B2结构有序状态下是顺磁性的，而无序状态和向A2（或bcc）结构的过渡则产生铁磁性，这使得通过掩模模板离子辐照进行横向图图化成为可能。在建议的36个月的项目中，我们将研究这种基于feal的横向纳米结构的磁态，磁化反转和自旋动力学，并解决周期性FM-PM界面上出现的现象。我们提出使用多频铁磁共振（FMR）技术来研究自旋动力学。项目的第一部分致力于双层结构，其中将相应地了解FeAl在PM和FM状态下作为自旋汇和自旋源的性质，并分析磁性界面的作用。然后，通过光刻掩模离子辐照产生的横向图案纳米结构以及聚苯乙烯纳米颗粒的自组装单层将被解决。为了更好地理解自旋动力学研究的结果，我们将对嵌入FM纳米结构的磁化强度、矫顽力、各向异性等静态磁性能进行分析。特别是，我们的研究旨在揭示由FM-PM界面产生角动量电流控制的横向自旋泵浦，以及迄今为止仅在磁性多层材料中观察到的自旋汇驱动的磁矩激励。考虑到双磁振子散射过程的影响，我们将对薄膜内磁性周期性调制的新型系统中的磁阻尼进行系统的研究。该项目将阐明在垂直FM/PM界面的横向结构中发生的现象的特殊性，并为进一步开发自旋电子学和磁学中复杂的人工磁性景观奠定基础。

The transition metal alloys whose magnetic properties are sensitive to structural disordering offer a unique opportunity for fabrication of laterally patterned magnetic nanostructures. Such artificial magnetic landscapes with periodical distribution of adjacent ferromagnetic (FM) and paramagnetic (PM) areas are promising for exploitation of nanoscale spin-dependent phenomena. They can be created using ion beam irradiation of the Fe60Al40 alloy. This material is paramagnetic in the B2 structurally ordered state while the disordering and transition to A2 (or bcc) structure induces ferromagnetism, which makes it possible to perform lateral patterning via ion irradiation through mask templates. Within the suggested 36-months project we offer to investigate the magnetic state, magnetization reversal and spin dynamics of such FeAl-based lateral nanostructures and address the phenomena arising at periodical FM-PM interfaces. We offer to use a multifrequency Ferromagnetic Resonance (FMR) technique for the investigation of the spin dynamics. The first part of project is devoted to bilayer structures where understanding the properties of FeAl acting as spin sink and spin source in PM and FM states, correspondingly, will be achieved as well as the role of the magnetic interface will be analyzed. Then, laterally patterned nanostructures produced by ion irradiation through lithographic masks as well as self-assembled monolayers of polystyrene nanoparticles will be addressed. Analysis of static magnetic properties such as magnetization, coercivity, anisotropy depending on the structural and size parameters of embedded FM nanostructures will be performed in order to understand the results of the spin dynamics study. In particular, our research is aimed to the revealing of lateral spin pumping governed by the generation of an angular momentum current at the FM-PM interface, and spin-sink driven excitation of magnetic moment which was observed so far only in magnetic multilayers. We will perform a systematic study of magnetic damping in such novel systems with periodical modulation of magnetic properties within the thin films, taking into account the influence of two-magnon scattering processes. This project will shed some light to the specificity of phenomena occurring in lateral structures with vertical FM/PM interfaces and serve as a base for further exploitation of complex artificial magnetic landscapes in spintronics and magnonics.