Modification of Magnetic Stability of Co Single Atoms on Pt(111) by Dimer Formation

Abstract

Novel magnetic properties of very small nanostructures have attracted broad interests in the fields of nanoscience and nanotechnology. The magnetic stability of such nanostructures relies on the magnetic anisotropy and magnetization dynamics. These properties were investigated for single Co atoms on Pt(111) using low-temperature scanning tunneling microscopy. The atomic manipulation capabilities of scanning tunneling microscopy allow to extend the study to Co dimers. Information on the magnetic anisotropy and lifetime of magnetically excited states of single atoms and dimers was achieved simultaneously with inelastic tunneling spectroscopy. Manufactured dimers consist of adatoms in nearest-neighbor fcc-hcp sites. For adatoms this close, a strong direct exchange interaction of 14 meV/h² was found, much larger than the weak long-range indirect Ruderman-Kittel-Kasuya-Yoshida interaction. [DOI: 10.1380/ejssnt.2011.237]