Trapping of carbon at 181Hf in platinum

Using the TDPAC-technique after ion implantation of 181Hf into Pt, a defect, trapped at the 181Hf probe atoms after annealing at 630 K to 850 K, could be identified as a carbon impurity atom. Measurements in a Pt single crystal showed a <110>-symmetry axis of the associated axially symmetric electric field gradient with a preferred direction almost parallel to the normal vector of the crystal surface. This leads to the conclusion that single carbon atoms are trapped on regular lattice sites next to the Hf probe and a strong interaction of these Hf-C complexes either with the collision cascades produced during the Hf implantations or the crystal surface must be assumed. (author)