Aharonov-Bohm oscillation in a ferromagnetic ring
Aharonov-Bohm oscillation in a ferromagnetic ring
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铁磁环中的阿哈罗诺夫-玻姆振荡
DOI：
10.1103/physrevb.69.054420
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发表时间：
2003
影响因子：
3.7
通讯作者：
B. Barbara
中科院分区：
文献类型：
--
作者：
G. Tatara;H. Kohno;E. Bonet;B. Barbara
从理论上研究了铁磁薄环在扩散状态下的Aharonov-Bohm效应。除了自旋轨道相互作用外，我们还包括自旋波激发和自旋分裂，它们被认为是铁磁体在低温下脱相的主要来源。结果表明，自旋分裂杀死了cooperon的自旋翻转通道，但保留了自旋守恒通道。为了实验证实弱局域化和周期为h/2e的Aharonov-Bohm振荡等干涉效应（由合作子描述），我们需要通过轨道运动抑制占主导地位的消相。为了做到这一点，我们建议在薄膜或薄环上进行实验，磁化和外场垂直于薄膜，在这种情况下，样品内部的有效场等于外场（磁化不加起来）。首先施加足够强的磁场以使磁化饱和，然后进行测量直至零场，保持磁化接近饱和，以避免畴形成（如果矫顽力场足够大，也可以研究负场）。
Aharonov-Bohm effect in a ferromagnetic thin ring in diffusive regime is theoretically studied by calculating the cooperon and diffuson. In addition to the spin-orbit interaction, we include the spin-wave excitation and the spin splitting, which are expected to be dominant sources of dephasing in ferromagnets at low temperatures. The spin splitting turns out to kill the spin-flip channel of cooperon but leaves the spin-conserving channel untouched. For the experimental confirmation of interference effect (described by cooperons) such as weak localization and Aharonov-Bohm oscillation with period h/2e, we need to suppress the dominant dephasing by orbital motion. To do this we propose experiments on a thin film or thin ring with magnetization and external field perpendicular to the film, in which case the effective field inside the sample is equal to the external field (magnetization does not add up). The field is first applied strong enough to saturate the magnetization and then carrying out the measurement down to zero field keeping the magnetization nearly saturated, in order to avoid domain formations (negative fields may also be investigated if the coercive field is large enough).