Micromagnetic simulations of vortex-state excitations in soft magnetic nanostructures
Micromagnetic simulations of vortex-state excitations in soft magnetic nanostructures
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DOI：
10.1103/physrevb.70.172408
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发表时间：
2004-11-01
影响因子：
3.7
通讯作者：
Vukadinovic, N
中科院分区：
文献类型：
--
作者：
Boust, F;Vukadinovic, N
采用三维动态微磁学模拟方法，在0.2-20 GHz频率范围内研究了具有涡旋型磁性结构的坡莫合金纳米点的动态磁化率谱随点厚度（10 nm ≤ L（z）≤ 80 nm）的变化规律.除了低频涡旋平移模式（涡旋核心的回转运动），第二涡旋核心模式在更高的频率下被揭示为更厚的纳米点（面内泵浦场）。该模式的共振频率随点厚度的增加而迅速降低，其来源于沿沿着点法向轴的非均匀涡旋结构。更高的频率模式也观察到在平面内和垂直泵浦场的方向，并对应于大多数的自旋激发定位在涡核之外。讨论了利用共振实验检测单个纳米点内两种涡核模式的可能性，并根据色散关系频率与垂直静磁场的关系进行了讨论。
The dynamic susceptibility spectra of Permalloy nanodots, supporting a vortex-type magnetic configuration, are studied within the frequency range 0.2-20 GHz as a function of dot thickness (10 nmless than or equal toL(z)less than or equal to80 nm) by means of three-dimensional dynamic micromagnetic simulations. In addition to the low-frequency vortex translation mode (gyrotropic motion of the vortex core), a second vortex core mode is revealed at a higher frequency for thicker nanodots (in-plane pumping field). This mode whose resonance frequency decreases rapidly with increasing dot thickness originates from the nonuniform vortex structure along the dot normal axis. Higher frequency modes are also observed for both in-plane and perpendicular pumping field orientations and correspond mostly to spin excitations localized outside the vortex core. The possible detection of the two vortex core modes within an individual nanodot using resonance experiments is discussed on the basis of the dispersion relation frequency versus perpendicular static magnetic field.