DOMAIN GROWTH OF DY2O3 BUFFER LAYERS ON SRTIO3

Dy2O3 layers have been grown on SrTiO3 by molecular beam epitaxy. X-ra y and electron diffraction patterns clearly show that Dy2O3 grows epit axially on SrTiO3 with {100} planes parallel to the substrate surface. Transmission electron microscopy reveals that the Dy2O3 film breaks u p into small domains (10-40 nm). This leads to the formation of terrac es which limits the structural perfection of thin overgrown DyBa2Cu3O7 by introducing steps and small misorientations (within 3-degrees). Th e resulting surface corrugation does not preclude the growth of epitax ial c-axis DyBa2Cu3O7 films with a T(c0) of 86 K. Crystallographic ana lysis and image calculations show that the domain growth of Dy2O3 is a ssociated with the formation of 90-degrees rotation twins.