Real time observation of partial dislocations in thin colloidal crystals

We use laser diffraction microscopy to visualize in real time the motion of partial dislocations in thin colloidal crystals confined in flat capillaries. The results show that the formation of partial dislocation loops with their associated stacking faults is an energetically preferred strain-relaxation channel for colloidal crystals. The local residual stress in the crystal can be estimated by measuring the velocity of the dislocations. Two types of interactions between the dislocations are observed, namely, that between two dislocations in two intersecting slide planes and that between two dislocations in two parallel slide planes.