Instituto de Ciencia de Materiales de Madrid (CSIC), Madrid, Spain.
Nanotechnology. 2010 Jun 25;21(25):255301. doi: 10.1088/0957-4484/21/25/255301. Epub 2010 May 28.
This work presents an analysis of the in-plane magnetization reversal mechanisms of Fe nanowires, with widths from 100 nm to 1 microm, fabricated in epitaxial Au(001)/Fe(001)/MgO(001) thin films by means of focused ion and electron beam lithographies, with either positive or negative resist. The experimental results show that the switching mechanisms and hysteresis are almost exclusively functions of the dimensions of the wires and of the Fe intrinsic properties, with minor influence of the specific fabrication route employed upon optimization of nanostructure parameters in terms of crystallinity and morphology, and well defined and reproducible geometry. The reversal processes evolve from wall pinning at low angles between the applied field and the axis of the wires to basically uniform magnetization rotation at high angles. This behaviour can be described in terms of single spin configurations, thus ruling out the formation of multidomain structures even at high angles. The ability to achieve these high quality and well controlled nanowires allowed us to develop an analytical model, based on uniform magnetization configurations considering just the intrinsic Fe properties and the shape and dimensions of the wires. This simple approach provides a very good qualitative and quantitative agreement with the experimental results, thus evidencing the relatively small role of other extrinsic factors in the magnetization processes.
这项工作分析了平面内磁化反转机制的铁纳米线，宽度从 100nm 到 1 微米，通过聚焦离子束和电子束光刻，使用正或负的抗蚀剂，在外延 Au(001)/Fe(001)/MgO(001)薄膜中制造而成。实验结果表明，开关机制和磁滞几乎完全是纳米线尺寸和铁的固有特性的函数，在优化纳米结构参数方面，采用特定的制造路线的影响较小，在结晶度和形态方面具有良好的定义和可重复性的几何形状。反转过程从低角度下的壁钉扎（磁场与纳米线轴之间的角度）到高角度下的基本均匀磁化旋转演变。这种行为可以用单自旋构型来描述，从而排除了即使在高角度下也会形成多畴结构的可能性。能够实现这些高质量和良好控制的纳米线，使我们能够开发出一种基于均匀磁化配置的分析模型，该模型只考虑铁的固有特性以及纳米线的形状和尺寸。这种简单的方法与实验结果非常吻合，定性和定量都很好，从而证明了其他外在因素在磁化过程中相对较小的作用。
