Strain fields at contacts between small particles.

Stress fields between interacting small particles ( approximately 100 nm) have been investigated by transmission electron microscopy. The background for these TEM observations is discussed in terms of adhesion stress fields (due to surface forces), the action of an applied point force, possibly magnetic, and dislocations or misfit strains due to an unfavorable matching of crystal lattices at the grain boundary. A further explanation might be sought along the line "squeezed-in oxide" which can be visualized as a coherent particle or a dislocation loop. Accompanying theoretical calculations have been performed and compared with the experimental results.