Direct Evidence for Dechanneling of 40 kV Gold Ions at Planar Defects in Silver and Gold

Thin single crystal sandwiches consisting of silver‐gold‐silver layers were prepared by epitaxial vapor deposition on (100) cleaved rocksalt. These specimens contained numerous (111) planar faults (coherent twins and stacking faults) extending through them at an angle of 54.7° with the surface. After bombardment along [100] with 40 ke V gold ions the middle gold layer was removed and examined by transmission electron microscopy. Zones free of radiation damage were found directly adjacent to the planar faults. These zones were a result of a shadowing effect caused by the defocusing of the incoming ions by the extensions of the planar defects into the upper silver layer (which were present during the bombardment). Evidence was also found for the production of excess defects directly at the planar defect surfaces in the gold layer due to dechanneling. The geometry of the blocking of [100] channels in a f.c.c. lattice by (111) planar faults is described.