Electronic transport properties and orientation of individualMn12single-molecule magnets

Abstract

Individual ${\text{Mn}}_{12}$ single-molecule magnets have been investigated by means of scanning tunneling spectroscopy at room temperature. Current-voltage characteristics of a ${\text{Mn}}_{12}$ derivative are studied in detail and compared with simulations. A few-parameter scalar model for ballistic current flow through a single energy level is sufficient to describe the main features observed in scanning tunneling spectra of individual ${\text{Mn}}_{12}$ molecules and offers a deeper insight into the electronic transport properties of this class of single-molecule magnets. In addition, distance-voltage spectroscopy performed on individual ${\text{Mn}}_{12}$ molecules reveals a possibility to identify the orientation of the molecular easy axis. The results indicate a preferential orientation of the easy axis of the molecules nearly perpendicular to the surface.