Growth,perfection and antiferromagnetic domain structure of epitaxial cobalt oxide

Uniform single crystals of cobalt oxide have been grown over a wide range of temperature (210° C) by vapour hydrolysis of cobalt bromide on to (001) cleavage faces of magnesium oxide. Thicker crystals have been grown by this technique than previously reported, and the dependence of the growth on the experimental parameters is presented.Optical and X-ray topographic techniques have been used to study the distribution of imperfections and antiferromagnetic domains in these crystals. The appearance of plastic deformation at the growth surface in crystals grown at high temperatures is a result of the combined stresses induced by differential thermal contraction of overgrowth and substrate, and the presence of growth striations throughout the bulk of the crystals. The complexity of the antiferromagnetic domain structure, which is sensitive to crystal thickness, is a direct result of the inhibiting effect of the substrate and the misfit associated with the antiferromagnetic tetragonal distortion.These results on cobalt oxide are compared and contrasted to those previously reported on nickel oxide grown under similar conditions.