The controlled production of surface defects by ion irradiation and nano-indentation techniques was discussed. The characterisation of novel types of defects was emphasized, among those: quasi 2-dimensional dislocation dipoles following coalescence at the surface of the vacancies induced by the irradiation and `mesas' and `winding-loops' as dislocation configurations originated by nano-indentation. The relationship between the latter defects and the onset of crystal plasticity was examined.

Characterising and Controlling Surface Defects. E.Carrasco, O.Rodríguez de la Fuente, M.A.González, J.M.Rojo: European Physics Journal B, 2004, 40[4], 421-6