Cantilever (torque) detected multifrequency electron spin resonance spectroscopy of halfmetallic compounds and endohedral metallofullerenes

悬臂（扭矩）检测半金属化合物和内嵌金属富勒烯的多频电子自旋共振光谱

• 批准号: 321732198
• 负责人: Dr. Alexey Alfonsov, Ph.D.
• 金额: --
• 依托单位: Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (IFW) e.V.
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/321732198?language=en
• 关键词: Cantilever; torque; detected; multifrequency; electron

In this project we propose to build a highly sensitive multifrequency cantilever-based (torque-detected) electron spin resonance (ESR) spectrometer, and to use it for studies of magnetic anisotropic properties of halfmetallic ferromagnets and endohedral metallofullerenes. Magnetic anisotropy always goes side by side with other fundamental properties, such as electronic correlations in transition metal oxides, in the metallic alloys, or in all kinds of molecular magnets (MM), including endohedral metallofullerenes (EMF). Therefore the study of the magnetic anisotropy provides direct insights into the intrinsic properties of different materials. This can further lead to the observation of new phenomena, or to the improvement of the known properties, so that the material can find technological applications. In the case of halfmetallic ferromagnets magnetic anisotropy as well as such dynamic property as a damping are responsible for the stability of the magnetization and for the ability to switch the magnetic state. Magnetic anisotropy in EMFs, which exhibit single molecular magnet behavior, could yield long living quantum states with zero-field relaxation times reaching several hours. For these materials the size of the sample plays a crucial role: metallic alloys promising for spintronics application has to be made as a thin, nm-size, films, in order to fulfill the requirements for building a device; molecular magnets, such as EMFs, where each molecule has a nanometer size, are especially interesting when deposited on the substrate as single layer. In order to have full access to the magnetic properties it is essential to measure ESR on above mentioned compounds at various frequencies, magnetic fields and at different angles between the sample and the applied magnetic field. This is not always possible in the standard ESR setups, due to a lack of sensitivity, or due to the restriction in frequency, strength and orientation of magnetic field. Cantilevers have an extremely high sensitivity, which is almost independent of the microwave frequency and magnetic field, and it is relatively easy to align them. This makes us confident that the constructed cantilever detected ESR setup will enable to explore static and dynamic magnetic anisotropic properties of halfmetallic ferromagnets and endohedral metallofullerenes.

在这个项目中，我们建议建造一个高灵敏度的多频悬臂梁（扭矩检测）电子自旋共振（ESR）光谱仪，并用它来研究半金属铁磁体和内嵌金属富勒烯的磁各向异性特性。磁各向异性总是与其他基本特性并存，例如过渡金属氧化物、金属合金或各种分子磁体 (MM)（包括内嵌金属富勒烯 (EMF)）中的电子相关性。因此，磁各向异性的研究可以直接洞察不同材料的固有特性。这可以进一步导致新现象的观察，或者已知特性的改进，从而使材料能够找到技术应用。在半金属铁磁体的情况下，磁各向异性以及阻尼等动态特性负责磁化的稳定性和切换磁状态的能力。 EMF 中的磁各向异性表现出单分子磁体行为，可以产生长寿命的量子态，零场弛豫时间可达数小时。对于这些材料，样品的尺寸起着至关重要的作用：有希望用于自旋电子学应用的金属合金必须制成纳米尺寸的薄膜，以满足构建器件的要求；分子磁体，例如 EMF，其中每个分子都具有纳米尺寸，当作为单层沉积在基板上时特别有趣。为了充分了解磁性，必须在不同频率、磁场以及样品与施加磁场之间的不同角度下测量上述化合物的 ESR。由于缺乏灵敏度，或者由于磁场频率、强度和方向的限制，这在标准 ESR 设置中并不总是可行。悬臂梁具有极高的灵敏度，几乎不受微波频率和磁场的影响，并且相对容易对准。这使我们相信，所构建的悬臂检测 ESR 装置将能够探索半金属铁磁体和内嵌金属富勒烯的静态和动态磁各向异性特性。