An experimental study of the influence of film edges and imperfections on buckling morphologies of quenched iron films

Iron films, quenched by silicone oil during deposition, have been prepared on glass substrates by a DC-magnetron sputtering method. The role of film edges and imperfections on the morphologies of buckle driven delaminations in the films has been investigated. The buckling patterns are found to initiate usually from areas such as the film edges, spreading fronts of silicone oil and other imperfections in the films. When the buckling patterns grow near the fronts of silicone oil, they tend to form disordered telephone cord buckle networks. When the patterns initiate from the film edges, they generally have first a straight-sided shape perpendicular to the edges, and then propagate a few micrometers apart in bifurcation or telephone cord structure. The growth of the buckling patterns can be well controlled by introducing some imperfections into the glass substrates before deposition.