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arXiv · 1310.6733

Etching of Cr tips for scanning tunneling microscopy of cleavable oxides

Dennis Huang·Stephen Liu·Ilija Zeljkovic·J. F. Mitchell·Jennifer E. Hoffman
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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 La$_{1.4}$Sr$_{1.6}$Mn$_2$O$_7$ to evaluate the spin characteristics of the Cr tip, replacing the UHV-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.

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Dennis Huang, Stephen Liu, Ilija Zeljkovic, J. F. Mitchell, Jennifer E. Hoffman. 2013-10-24. Etching of Cr tips for scanning tunneling microscopy of cleavable oxides. https://doi.org/10.1063/1.4976567

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