Molecular beam epitaxy of layered Dy-Ba-Cu-O compounds

Heteroepitaxial Dy-Ba-Cu-O films have been grown in situ on SrTiO3 substrates using an oxygen plasma beam and elemental source beams in a modified molecular beam epitaxy machine. By periodically shuttering the Dy and Ba beams during growth, flat surfaces of layered Dy-Ba-Cu-O compounds have been obtained. Periodic oscillations in the intensity of the in situ reflection high-energy electron diffraction pattern were observed during shuttered growths. Depending on growth conditions, the as-grown layers have ranged from insulating to superconducting with onset temperatures above 60 K.