用于可裂解氧化物扫描隧道显微镜的铬尖端蚀刻

Etching of Cr tips for scanning tunneling microscopy of cleavable oxides.

作者信息

Huang Dennis, Liu Stephen, Zeljkovic Ilija, Mitchell J F, Hoffman Jennifer E

机构信息

Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.

Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.

出版信息

Rev Sci Instrum. 2017 Feb;88(2):023705. doi: 10.1063/1.4976567.

DOI:10.1063/1.4976567

PMID:28249529

Abstract

We report a detailed three-step roadmap for the fabrication and characterization of bulk Cr tips for spin-polarized scanning tunneling microscopy. Our strategy uniquely circumvents the need for ultra-high vacuum preparation of clean surfaces or films. First, we demonstrate the role of ex situ electrochemical etch parameters on Cr tip apex geometry, using scanning electron micrographs of over 70 etched tips. Second, we describe the suitability of the in situ cleaved surface of the layered antiferromagnet LaSrMnO to evaluate the spin characteristics of the Cr tip, replacing the ultra-high vacuum-prepared test samples that have been used in prior studies. Third, we outline a statistical algorithm that can effectively delineate closely spaced or irregular cleaved step edges, to maximize the accuracy of step height and spin-polarization measurements.

摘要

我们报告了一种用于制造和表征用于自旋极化扫描隧道显微镜的块状铬尖端的详细三步路线图。我们的策略独特地避免了对清洁表面或薄膜进行超高真空制备的需求。首先，我们使用70多个蚀刻尖端的扫描电子显微镜图像，展示了非原位电化学蚀刻参数对铬尖端顶点几何形状的作用。其次，我们描述了层状反铁磁体LaSrMnO的原位解理表面用于评估铬尖端自旋特性的适用性，取代了先前研究中使用的超高真空制备的测试样品。第三，我们概述了一种统计算法，该算法可以有效地描绘紧密间隔或不规则的解理台阶边缘，以最大限度地提高台阶高度和自旋极化测量的准确性。