Formation and structure of misfit dislocations at the La2Zr2O7-Y2O3-stabilized ZrO2 (001) reaction front during vapour-solid reaction

La-2 Zr2O7 (LZO)-based pyrochlore islands were grown on a Y2O3-stabilized ZrO2 (YSZ) (001) single-crystal surface by the reaction between La2O3 vapour and the crystal. A network of interfacial edge dislocations with line directions [100] and [010] and Burgers vectors. (a(s)/2)[101] and (a(s)/2)[011] respectively (a(s) being the lattice parameter of the YSZ) was observed at the moving LZO-YSZ reaction front. The interface-parallel component of the Burgers vectors accommodates the LZO-YSZ lattice mismatch of +5.0%, while the perpendicular component causes a slight tilt of the LZO lattice with respect to the YSZ lattice. The dislocation half-loops nucleate and glide on inclined {101} planes at the edges of the four corners of the growing islands.