Subnanosecond vortex transformation in ferromagnetic film elements observed by stroboscopic wide-field Kerr microscopy
Subnanosecond vortex transformation in ferromagnetic film elements observed by stroboscopic wide-field Kerr microscopy
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频闪宽视场克尔显微镜观察铁磁薄膜元件的亚纳秒涡旋转变
DOI：
10.1063/1.1850832
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发表时间：
2005
影响因子：
3.2
通讯作者：
L. Schultz
中科院分区：
文献类型：
--
作者：
A. Neudert;J. McCord;R. Schäfer;L. Schultz
用时间分辨频闪宽场克尔显微术测量了直径为16μm、厚度为50nm的Ni_（81）Fe_（19）盘的磁化动力学。采用高功率Nd：YVO4固体激光器倍频照明，获得了时间分辨率。磁化强度的基态是用一个700 ps宽的脉冲激发的，脉冲幅度约为1.2kA闪烁。在由于脉冲磁场引起的磁化强度和涡旋位移的快速旋转之后，磁化强度缓慢地弛豫回到基态。在涡旋松弛期间，我们在元件的中心观察到拉伸的涡旋结构，其可以是180°壁或具有切换的芯磁化的两个涡旋的叠加。
The magnetization dynamics of a Ni81Fe19 disk of 16μm diameter and 50nm thickness was measured by time-resolved stroboscopic wide-field Kerr microscopy with a temporal resolution of less than 25ps. Time resolution is obtained by illumination with a frequency-doubled high-power Nd:YVO4 solid-state laser. The ground state of the magnetization is excited with a 700‐ps-wide pulse of about 1.2kA∕m amplitude. After a fast rotation of magnetization and vortex displacement due to the pulsed magnetic field the magnetization slowly relaxes back to the ground state. During relaxation of the vortex we observe in the center of the element a stretched vortex structure that could be a 180° wall or a superposition of two vortices with switched core magnetization.