The interface of laser-deposited Fe/Ag multilayers: evidence for the "subsurface growth mode" during pulsed-laser deposition and examination of the bcc-fcc transformation
S. Fahler et al., The interface of laser-deposited Fe/Ag multilayers: evidence for the "subsurface growth mode" during pulsed-laser deposition and examination of the bcc-fcc transformation, APPL PHYS A, 69, 1999, pp. S459-S462
One of the most significant features of pulsed-laser deposition (PLD) in va
cuum as compared to conventional deposition methods is that a significant n
umber of ions are deposited with a high kinetic energy of about 100 eV. Usi
ng Fe/Ag multilayers, we show that the deposition of energetic particles du
ring PLD leads to implantation into the existing film. The film growth can
be described by a growth mode in which the material does not grow on top, b
ut rather within the topmost few monolayers of the already deposited film.
To examine this "subsurface growth", in situ resistance measurements and el
ectron diffraction experiments were performed. Resistance measurements show
a drop in conductance after beginning a new Fe layer, an effect attributed
to implantation and alloying at the interface. Electron diffraction experi
ments allow the observation of the structural change from fcc-Ag to bcc-Fe
and vice versa. These experiments are interpreted by the use of a Pain tran
sformation to describe a homogeneous transformation between the two structu
res.