Bulk Cr tips for scanning tunneling microscopy and spin-polarized scanning tunneling microscopy

TL;DR

This paper presents a simple method for preparing bulk Cr tips for STM and SP-STM, demonstrating their high-resolution capabilities and magnetic contrast, which could enhance various STM experiments.

Contribution

A novel, reliable preparation method for bulk Cr tips enabling high-resolution STM and SP-STM with magnetic contrast.

Findings

Cr tips achieve atomic resolution on surfaces.

Cr tips allow observation of rest atoms on Si(111)-7x7.

Cr(001) surface shows magnetic contrast in SP-STM.

Abstract

A simple, reliable method for preparation of bulk Cr tips for Scanning Tunneling Microscopy (STM) is proposed and its potentialities in performing high-quality and high-resolution STM and Spin Polarized-STM (SP-STM) are investigated. Cr tips show atomic resolution on ordered surfaces. Contrary to what happens with conventional W tips, rest atoms of the Si(111)-7x7 reconstruction can be routinely observed, probably due to a different electronic structure of the tip apex. SP-STM measurements of the Cr(001) surface showing magnetic contrast are reported. Our results reveal that the peculiar properties of these tips can be suited in a number of STM experimental situations.