  CaF2(111) single crystal surfaces have been irradiated with swift heavy ions
under oblique angles resulting in chains of nanosized hillocks. In order to
characterize these nanodots with respect to their conductivity we have applied
non-contact atomic force microscopy using a magnetic tip. Measurements in UHV
as well as under ambient conditions reveal a clearly enhanced electromagnetic
interaction between the magnetic tip and the nanodots. The dissipated energy
per cycle is comparable to the value found for metals, indicating that the
interaction of the ion with the target material leads to the creation of
metallic Ca nanodots on the surface.
