Sub-nanosecond resolution x-ray magnetic circular dichroism photoemission electron microscopy of magnetization processes in a permalloy ring
Sub-nanosecond resolution x-ray magnetic circular dichroism photoemission electron microscopy of magnetization processes in a permalloy ring
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坡莫合金环磁化过程的亚纳秒分辨率 X 射线磁圆二色性光电发射电子显微镜
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发表时间：
2005
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通讯作者：
G. Schönhense
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作者：
D. Neeb;A. Krasyuk;A. Oelsner;S. Nepijko;H. Elmers;A. Kuksov;Carsten Schneider;G. Schönhense
80 µm外径微结构坡莫合金环的快速磁化过程和30 nm的厚度已经通过利用X射线磁性圆二色性作为磁性对比机制的光发射电子显微镜观察到。作为一个高速探头，我们采用同步辐射脉冲在ESRF（格勒诺布尔）在16聚束模式，产生的光子脉冲的105 ps的半高宽与周期为176 ns。利用电流脉冲通过在其表面光刻制备磁性结构的共面波导产生快磁场脉冲。一个频闪泵探测设置与可变的时间延迟之间的字段脉冲和光子脉冲，使我们能够采取的磁畴结构的动态响应的快照。我们观察到相干磁化旋转的前沿部分的字段脉冲，形成的特征域图案（“洋葱状态”）在高原地区的脉冲和快速形成的条纹域图案（非相干磁化旋转）的字段脉冲的后沿部分。数值模拟证实了频闪图像系列的基本特征。
Fast magnetization processes in a microstructured permalloy ring with 80 µm o.d. and 30 nm thickness have been observed by photoemission electron microscopy exploiting x-ray magnetic circular dichroism as the magnetic contrast mechanism. As a high speed probe we employed synchrotron radiation pulses at the ESRF (Grenoble) operated in 16-bunch mode, yielding photon pulses of 105 ps FWHM with a period of 176 ns. Fast magnetic field pulses have been generated by means of current pulses through coplanar waveguides with the magnetic structure being lithographically prepared on their surface. A stroboscopic pump–probe set-up with a variable time delay between the field pulse and photon pulse allowed us to take snapshots of the dynamic response of the magnetic domain structure. We observed coherent magnetization rotation during the leading edge part of the field pulse, the formation of a characteristic domain pattern (‘onion state’) in the plateau region of the pulse and the fast formation of a striped domain pattern (incoherent magnetization rotation) during the trailing edge part of the field pulse. A numerical simulation confirmed essential features of the stroboscopic image series.