Ferromagnetic resonance with Scanning Tunneling Microscopy

扫描隧道显微镜的铁磁共振

• 批准号: 366208634
• 负责人: Professor Dr. Wulf Wulfhekel
• 金额: --
• 依托单位: Physikalisches Institut (PHI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/366208634?language=en
• 关键词: Ferromagnetic; resonance; Scanning; Tunneling; Microscopy

This project aims at the establishment of a new experimental method that combines high resolution spin-polarized scanning tunneling microscopy (Sp-STM) with the spin torque diode effect to realize spatially resolved ferromagnetic resonance and to study the magnetization dynamics of individual nano-sized magnetic structures including their magnetic eigen-modes. We mix a rf-voltage to the bias of the tunneling junction in order to periodically excite the magnetic sample by the resulting periodic spin torque. When hitting the resonance frequency, the combined periodic magnetization oscillations and the oscillating bias lead via the spin-dependent tunneling to a rectified dc-current that can be detected using conventional current amplifiers. This effect is known as the spin diode effect. In preliminary experiments we succeeded to compensate for transmission effects such that a constant excitation voltage can be reached as function of excitation frequency and have observed resonance signals in magnetic skyrmions. In this proposal, we intend to extend the frequency range (currently limited to 3GHz) to above 13 GHz and enlarge the excitation amplitude by an order of magnitude such that: 1. resonance phenomena of magnetic vortices can be studied in detail, 2. gyration and breathing modes of skyrmions can be detected and be compared with numerical simulations and 3. from the line shape of the resonance, contributions of the Slonczweski and field like spin torques can be determined.

本项目旨在建立一种新的实验方法，将高分辨率自旋偏振扫描隧道显微镜(Sp-STM)与自旋扭矩二极管效应相结合，实现空间分辨铁磁共振，并研究单个纳米磁性结构的磁化动力学及其磁本征模。我们将射频电压混合到隧道结的偏置上，以便通过产生的周期性自旋扭矩周期性地激励磁性样品。当触及谐振频率时，组合的周期性磁化振荡和振荡偏置导联通过自旋相关的隧道作用形成整流的直流电流，这可以使用传统的电流放大器检测到。这种效应被称为自旋二极管效应。在初步的实验中，我们成功地补偿了传输效应，从而可以达到恒定的激发电压作为激发频率的函数，并观察到了磁天子的共振信号。在这个方案中，我们打算将频率范围(目前限制在3 GHz)扩展到13 GHz以上，并将激发幅度扩大一个数量级，以便：1.可以详细地研究磁涡旋的共振现象，2.可以探测到天子的自转和呼吸模式，并与数值模拟进行比较，3.从共振的线形可以确定SLonczweski和类似场的自旋力矩的贡献。

项目成果

Epitaxial growth of Co on stepped Ru(0001): Stabilization of CoRu magnetic surface alloy

Co 在阶梯状 Ru(0001) 上的外延生长：CoRu 磁性表面合金的稳定化

• DOI: 10.1016/j.susc.2019.121512
• 发表时间: 2020
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: R. Lopes;M. Hervé;L. Gerhard;W. Wulfhekel;M. D. Martins
• 通讯作者: M. D. Martins

Large tunneling anisotropic magnetoresistance mediated by surface states

表面态介导的大隧道各向异性磁阻

• DOI: 10.1103/physrevb.97.220406
• 发表时间: 2018
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: M. Hervé;T. Balashov;A. Ernst;W. Wulfhekel
• 通讯作者: W. Wulfhekel

Instability of skyrmions in magnetic fields

• DOI: 10.1063/5.0013488
• 发表时间: 2020-06
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Loic Mougel;P. M. Buhl;Ryohei Nemoto;T. Balashov;Marie Hervé;Julian Skolaut;T. Yamada;B. Dupé;W. Wulfhekel

Towards Laterally Resolved Ferromagnetic Resonance with Spin-Polarized Scanning Tunneling Microscopy

• DOI: 10.3390/nano9060827
• 发表时间: 2019-06-01
• 期刊: NANOMATERIALS
• 影响因子: 5.3
• 作者: Herve, Marie;Peter, Moritz;Wulfhekel, Wulf
• 通讯作者: Wulfhekel, Wulf