Statuto Nahuel, Hernàndez Joan Manel, Kent Andrew D, Macià Ferran
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, E-08193 Bellaterra, Spain. Dept. of Condensed Matter Physics, University of Barcelona, E-08028 Barcelona, Spain.
Nanotechnology. 2018 Aug 10;29(32):325302. doi: 10.1088/1361-6528/aac411. Epub 2018 May 11.
A spin-polarized current in a nanocontact to a magnetic film can create collective magnetic oscillations by compensating the magnetic damping. In particular, in materials with uniaxial magnetic anisotropy, droplet solitons have been observed-a self-localized excitation consisting of partially reversed magnetization that precesses coherently in the nanocontact region. It is also possible to generate topological droplet solitons, known as dynamical skyrmions (DSs). Here, we show that spin-polarized current thresholds for DS creation depend not only on the material's parameters but also on the initial magnetization state and the rise time of the spin-polarized current. We study the conditions that promote either droplet or DS formation and describe their stability in magnetic films without Dzyaloshinskii-Moriya interactions. The Oersted fields from the applied current, the initial magnetization state, and the rise time of the injected current can determine whether a droplet or a DS forms. DSs are found to be more stable than droplets. We also discuss electrical characteristics that can be used to distinguish these magnetic objects.
与磁性薄膜形成纳米接触的自旋极化电流可通过补偿磁阻尼来产生集体磁振荡。特别是，在具有单轴磁各向异性的材料中，已观测到液滴孤子——一种由部分反转磁化构成的自局域激发，其在纳米接触区域内相干进动。还能够产生被称为动态斯格明子（DSs）的拓扑液滴孤子。在此，我们表明产生DS的自旋极化电流阈值不仅取决于材料参数，还取决于初始磁化状态以及自旋极化电流的上升时间。我们研究了促进液滴或DS形成的条件，并描述了它们在没有Dzyaloshinskii-Moriya相互作用的磁性薄膜中的稳定性。外加电流产生的奥斯特场、初始磁化状态以及注入电流的上升时间能够决定形成的是液滴还是DS。已发现DS比液滴更稳定。我们还讨论了可用于区分这些磁性物体的电学特性。
