Current-induced resonance and mass determination of a single magnetic domain wall
Current-induced resonance and mass determination of a single magnetic domain wall
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DOI：
10.1038/nature03009
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发表时间：
2004-11-11
期刊：
影响因子：
64.8
通讯作者：
Tatara, G
中科院分区：
文献类型：
--
作者：
Saitoh, E;Miyajima, H;Tatara, G
磁畴壁（DW）是磁体中磁化结构的空间局部变化。这个拓扑物体被预测在低能量下表现为具有有限质量的复合粒子（1）。这种粒子将直接与电流以及磁场耦合，并且使用电流（2-8）对它的操纵对于高密度磁存储器（9）的开发特别感兴趣。DW质量设定这些装置的最终操作速度，但尚未通过实验确定。在这里，我们报告了在铁磁纳米线中的单个DW的动力学的直接观察，这表明这样的拓扑粒子具有非常小但有限的质量6.6x10（-23）kg。这种测量是通过在纳米线中制备可调的DW电势，并检测由振荡电流引起的DW的共振运动来实现的。共振还允许低电流操作，这在器件应用中是至关重要的; 10 μ m的DW位移由10（10）A m（-2）的电流密度引起。
A magnetic domain wall (DW) is a spatially localized change of magnetization configuration in a magnet. This topological object has been predicted to behave at low energy as a composite particle with finite mass(1). This particle will couple directly with electric currents as well as magnetic fields, and its manipulation using electric currents(2-8) is of particular interest with regard to the development of high-density magnetic memories(9). The DW mass sets the ultimate operation speed of these devices, but has yet to be determined experimentally. Here we report the direct observation of the dynamics of a single DW in a ferromagnetic nanowire, which demonstrates that such a topological particle has a very small but finite mass of 6.6x10(-23) kg. This measurement was realized by preparing a tunable DW potential in the nanowire, and detecting the resonance motion of the DW induced by an oscillating current. The resonance also allows low-current operation, which is crucial in device applications; a DW displacement of 10 mum was induced by a current density of 10(10) A m(-2).