Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
Nano Lett. 2013 Jun 12;13(6):2704-9. doi: 10.1021/nl400875z. Epub 2013 May 31.
We present a general methodology for measuring the Hall effect on nanostructures with one-dimensional (1D) nanowire morphology. Relying only on typical e-beam lithography, the methodology developed herein utilizes an angled electrode evaporation technique so that the nanowire itself is a shadow mask and an intimate sidewall contact can be formed for the Hall electrodes. A six-contact electrode scheme with offset transverse contacts is utilized that allows monitoring of both the longitudinal resistivity and the Hall resistivity which is extracted from the raw voltage from the transverse electrodes using an antisymmetrization procedure. Our method does not require the use of a highly engineered lithographic process to produce directly opposing Hall electrodes with a very small gap. Hall effect measurements on semiconducting iron pyrite (FeS2) nanowire devices are validated by comparing to Hall effect measurements in the conventional Hall geometry using FeS2 plate devices. This Hall effect measurement is further extended to MnSi nanowires, and the distinct anomalous Hall effect signature is identified for the first time in chiral magnetic MnSi nanowires, a significant step toward identifying the topological Hall effect due to skyrmions in chiral magnetic nanowires.
我们提出了一种通用的方法来测量具有一维（1D）纳米线形态的纳米结构的 Hall 效应。仅依靠典型的电子束光刻技术，本文所开发的方法利用了倾斜电极蒸发技术，使得纳米线本身成为一个阴影掩模，并且可以形成 Hall 电极的紧密侧壁接触。利用具有偏移横向接触的六接触电极方案，可以监测纵向电阻率和 Hall 电阻率，这是通过使用反对称化程序从横向电极的原始电压中提取的。我们的方法不需要使用高度工程化的光刻工艺来直接产生具有非常小间隙的 opposing Hall 电极。通过将铁 pyrite (FeS2) 纳米线器件的 Hall 效应测量结果与使用 FeS2 板器件的传统 Hall 几何结构中的 Hall 效应测量结果进行比较，验证了这种 Hall 效应测量方法。这种 Hall 效应测量方法进一步扩展到 MnSi 纳米线，首次在手性磁 MnSi 纳米线中识别出明显的反常 Hall 效应特征，这是在手性磁纳米线中识别 skyrmions 拓扑 Hall 效应的重要一步。
