H-induced plastic deformation of Gd thin films studied by STM.

Surface modification of thin Gd films during hydrogen absorption has been investigated on the nanometer scale by scanning tunneling microscopy. Two different types of surface pattern appear that can be attributed to hydrogen-induced plastic deformation processes within the Gd film. Disklike islands are formed first due to ${\mathrm{GdH}}_{2}$ precipitation and concomitant emission of extrinsic dislocation loops. At a later stage ramps appear on the surface as a result of glide displacements originating from misfit dislocations at the interface between the substrate and the thin film.