Omari K A, Hayward T J
Department of Materials Science and Engineering, University of Sheffield, Sheffield, S10 2TN, UK.
Sci Rep. 2017 Dec 19;7(1):17862. doi: 10.1038/s41598-017-17512-w.
Understanding dynamically-induced stochastic switching effects in soft ferromagnetic nanowires is a critical challenge for realising spintronic devices with deterministic switching behaviour. Here, we present a micromagnetic simulation protocol for qualitatively predicting dynamic stochastic domain wall (DW) pinning/depinning at artificial defect sites in NiFe nanowires, and demonstrate its abilities by correlating its predictions with the results of focused magneto-optic Kerr effect measurements. We analyse DW pinning configurations in both thin nanowires (t = 10 nm) and thick nanowires (t = 40 nm) with both single (asymmetric) and double (symmetric) notches, showing how our approach provides understanding of the complex DW-defect interactions at the heart of stochastic pinning behaviours. Key results explained by our model include the total suppression of stochastic pinning at single notches in thick nanowires and the intrinsic stochasticity of pinning at double notches, despite their apparent insensitivity to DW chirality.
理解软铁磁纳米线中动态诱导的随机开关效应是实现具有确定性开关行为的自旋电子器件的一项关键挑战。在此，我们提出一种微磁模拟方法，用于定性预测镍铁纳米线中人工缺陷位点处动态随机畴壁（DW）的钉扎/去钉扎，并通过将其预测结果与聚焦磁光克尔效应测量结果相关联来展示其能力。我们分析了具有单（不对称）和双（对称）缺口的细纳米线（t = 10 nm）和粗纳米线（t = 40 nm）中的DW钉扎构型，展示了我们的方法如何帮助理解随机钉扎行为核心的复杂DW-缺陷相互作用。我们的模型解释的关键结果包括厚纳米线中单缺口处随机钉扎的完全抑制以及双缺口处钉扎的固有随机性，尽管它们对DW手性明显不敏感。
