Magnetic imaging at the atomic level

Magnetic contrast at the atomic level has been observed for the first time in scanning tunneling microscopy experiments on a magnetite (Fe₃O₄(001)) surface using in-situ prepared ferromagnetic Fe tips. A periodic corrugation with a 12 Å periodicity is clearly observed along the rows of FeB-sites which corresponds to the repeat period of Fe²⁺ and Fe³⁺ along these rows. This periodicity is not observed by using non-magneticW tips although the rows of FeB-sites can be resolved as well. The magnetic contrast observed with Fe tips is attributed to the different spin configurations of the magnetic ions Fe²⁺ and Fe³⁺ in Fe₃O₄.