Vacuum tunneling of spin‐polarized electrons detected by scanning tunneling microscopy
Vacuum tunneling of spin‐polarized electrons detected by scanning tunneling microscopy
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扫描隧道显微镜检测自旋极化电子的真空隧道
DOI：
10.1116/1.585560
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发表时间：
1991
影响因子：
1.4
通讯作者：
R. Ruf
中科院分区：
文献类型：
--
作者：
R. Wiesendanger;D. Bürgler;G. Tarrach;A. Wadas;D. Brodbeck;H. Güntherodt;G. Güntherodt;R. Gambino;R. Ruf
我们证明，在超高真空中操作的扫描隧道显微镜（STM）可以对电子自旋敏感，从而对原子尺度的磁性结构敏感。实验使用提供高自旋极化电子的铁磁 CrO2 尖端进行。作为样品，我们使用了 Cr(001) 单晶，它提供了理想的磁测试结构。使用铁磁性 CrO2 尖端获得的实验结果与使用非磁性钨尖端获得的实验结果存在明显差异。我们给出了一个表达式，将隧道结的局部电子自旋极化与 STM 直接测量的量联系起来。我们还讨论了磁偶极子和交换力的可能贡献以及磁交换力显微镜的可行性。
We show that the scanning tunneling microscope (STM), operated in ultrahigh vacuum, can be made sensitive to the electron spin and therefore to magnetic structures down to the atomic scale. The experiments were performed with a ferromagnetic CrO2 tip providing electrons of high spin polarization. As sample, we used a Cr(001) single crystal which offers an ideal magnetic test structure. The experimental results obtained with the ferromagnetic CrO2 tip characteristically differ from those obtained with a nonmagnetic tungsten tip. We give an expression, relating the local electron spin polarization of the tunneling junction with quantities directly measurable with the STM. We also discuss possible contributions from magnetic dipole and exchange forces as well as the feasibility of magnetic exchange force microscopy.