Huang, DennisLiu, StephenZeljkovic, IlijaMitchell, J. F.Hoffman, Jenny2017-07-182017Huang, Dennis, Stephen Liu, Ilija Zeljkovic, J. F. Mitchell, and Jennifer E. Hoffman. 2017. “Etching of Cr Tips for Scanning Tunneling Microscopy of Cleavable Oxides.” Review of Scientific Instruments 88 (2) (February): 023705. doi:10.1063/1.4976567.0034-6748http://nrs.harvard.edu/urn-3:HUL.InstRepos:33464188We 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 La1.4Sr1.6Mn2O7 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.en-USJournal Article2017-06-2920172017-07-1810.1063/1.4976567