It was recalled that recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multi-layers had revealed the formation of misfit-strain reducing dislocation structures that were very similar to those observed experimentally. Similar simulations were reported here which revealed the formation of edge dislocations near to the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multi-layers. Unlike the misfit dislocations that accommodated lattice-mismatch, the dislocation structures observed here increased the mismatch strain energy. Stop-action observations of evolving atomic structures indicated that, during deposition onto the (111) surface of a face-centered cubic lattice, adatoms could occupy face-centered cubic sites or hexagonal close-packed sites. This resulted in the random formation of face-centered cubic and hexagonal close-packed domains; with dislocations at the domain boundaries. These dislocations permitted atoms to undergo a shift from face-centered cubic to hexagonal close-packed sites, or vice versa. These shifts led to missing atoms. Therefore, a later-deposited layer could have missing planes when compared to a previously deposited layer. This dislocation formation mechanism could create tensile stresses in face-centered cubic films. The probability that such dislocations would form was found to decrease rapidly under energetic deposition conditions.

Misfit-Energy Increasing Dislocations in Vapor-Deposited CoFe/NiFe Multilayers. X.W.Zhou, R.A.Johnson, H.N.G.Wadley: Physical Review B, 2004, 69[14], 144113 (10pp)