Fabrication of smooth surface on liquid phase epitaxially grown Y_1Ba_2Cu_3O_(7-#delta#) Films by mechanical polishing

摘要

We successfully created a smooth surface on liquid phase epitaxially (LPE) grown Y_1Ba_2Cu_3O_(7-#delta#) (YBCO) films by employing a mechanical polishing process. We used an alumina powder with an average grain diameter of 0.03#mu#m which was dispersed in oil for mechanical polishing, which made it possible to avoid a degradation of the Tc value for YBCO. While the as-grown surface of LPE-YBCO films contains various pyramidal structures with heights of about 400nm, the polished surface has only a roughness of 2 to 3nm as measured by a step profiler. A X_(min) value of 2.6precent according to Rutherford backscattering spectrometry suggests that the damage after mechanical polishing is negligible. After annealing in O_2 gas at 1 atm, the polished YBCO films transformed from tetragonal to orthorhombic phase and had a Tc value of about 91K.