In this work magnetic atoms on surfaces are studied with low-temperature scanning tunneling
microscopy. Motivated by the idea to use single atoms as magnetic bits the factors that allow
or prevent long-term stability of their magnetic moments are investigated. Lifetimes of up to
several minutes can be achieved for the magnetic moments of holmium atoms on a Pt(111) surface
resulting from the combined symmetries of the system. Corresponding theoretical calculations
are presented and evaluated.
