Hb. Groen et al., High-resolution transmission electron microscopy imaging of misfit-dislocation networks at Cu-MgO and Cu-MnO interfaces, PHIL MAG A, 79(9), 1999, pp. 2083-2101
Misfit dislocation networks at Cu-MgO and Cu-MnO {111}(metal)//{111}(oxide)
interfaces were studied with high-resolution transmission electron microsc
opy. Experimental results were compared with image simulations of tentative
atomic structures of the interface region derived from lattice statics cal
culations. The calculations take into account the two-dimensional misfit at
the interface, which is necessary given the high misfit and short repeat d
istances at the interfaces. The lattice statics calculations use simplified
potentials across the interface which capture essential characteristics th
at have emerged from recent experimental results and ab-initio calculations
. Trigonal networks of edge misfit locations with Burgers vectors 1/6[112]
and line direction [110] follow from these calculations. These misfit-dislo
cation networks have associated strain fields in the metal, stretching out
from the interface with approximately the repeat distance along the interfa
ce. These strain fields show up in image simulations (along [110] and [112]
directions) by characteristic but subtle periodic changes in contrast and
brightness as well as small displacements of spots. The experimental images
, also along [110] and [112] directions, showed similar characteristics but
they were difficult to detect, especially along [112] for the Cu-MnO inter
face, and may easily be missed. Judging from this evidence we conclude that
the proposed misfit-dislocation structure is in fact present at these inte
rfaces.