Topographic and Magnetic-Sensitive Scanning Tunneling Microscope Study of Magnetite

Abstract

The topographic and magnetic surface structure of a natural single crystal of magnetite (Fe₃0₄), a common mineral, has been studied from the submicrometer scale down to the atomic scale with a scanning tunneling microscope having nonmagnetic tungsten as well as ferromagnetic iron probe tips. Several different (001) crystal planes were imaged to atomic resolution with both kinds of tips. A selective imaging of the octahedrally coordinated Fe B-sites in the Fe-O planes, and even a selective imaging of the different magnetic ions Fe²⁺ and Fe³⁺, has been achieved, demonstrating for the first time that magnetic imaging can be realized at the atomic level.