Investigation of magnetization dynamics of vortices probed by high frequency scanning tunneling microscopy

在这个项目中，我们将研究纳米结构的磁化动力学，特别是磁涡流。测量是基于最近开发的高频扫描隧道显微镜，其时间分辨率低至120ps。这种方法是迄今为止唯一一种将空间分辨率低至原子尺度，高时间分辨率和自旋极化尖端局部激发磁系统的可能性结合在一起的方法。这将使研究磁化动力学下降到原子尺度。我们将探索这种新的可能性来研究涡旋结构对涡旋核心或缺陷的局部激励的响应。利用带状线的全局激励，我们的目标是对涡旋动力学进行原子分辨率的时间成像，以确定缺陷和外场对动力学的影响。我们将使用在W（110）上制备的Fe纳米岛，其高度约为7nm，横向长度约为100nm。采用分子束外延（MBE）原位制备。磁性缺陷是通过对低温沉积的外来原子进行原子操纵而产生的。对于自旋动力学的时间分辨成像，我们将直接在W（110）带状线上制备磁性纳米结构。

Within this project, we will investigate the magnetization dynamics of nanostructures, in particular, magnetic vortices. The measurements are based on a recently developed high-frequency scanning tunneling microscope, which exhibits time resolution down to 120 ps. This method is, so far, the only one which combines spatial resolution down to the atomic scale, high time resolution and the possibility of local excitation of the magnetic system by spin-polarized tips. This will allow to study magnetization dynamics down to the atomic scale. We will explore this novel possibility to study the response of the vortex structure to local excitations in defined distance to the vortex core or at defects. Using global excitation via striplines, we aim at a temporal imaging of the vortex dynamics with atomic resolution in order to pinpoint the influence of defects and external fields on the dynamics.We will use Fe nanoislands prepared on W(110), which exhibit a vortex at a height of about 7nm and lateral length scales of 100 nm. The preparation is performed in-situ using molecular beam epitaxy (MBE). Magnetic defects are created by atomic manipulation of foreign atoms deposited at low temperature. For the time-resolved imaging of the spin dynamics, we will prepare the magnetic nanostructures directly on a W(110) stripline.