GROWTH PROPERTIES OF Y1Ba2Cu3O7-delta THIN FILM ON CeO2(/MgO) BUFFER LAYER FOR THE BIEPITAXIAL BOUNDARY JUNCTION

Abstract

In the fabrication of Y1Ba2Cu3O7-delta (YBCO)/CeO2/MgO/SrTiO3 - YBCO/CeO2/SrTiO3 biepitaxial grain boundary junctions, the substrate temperature window for the growth of good quality superconduting YBCO overlayers on CeO2/MgO/SrTiO3 is lower and narrower than for growth of YBCO on CeO2/SrTiO3. Results of XRD 2 theta and phi scan measurements reveal that the lattice structure of the CeO2 layer on the MgO seed layer is 2 similar to 3 times more distorted than for CeO2 on a bare SrTiO3 substrate. It is interesting that the instability of the crystal formation of the YBCO layer on the CeO2/MgO/SrTiO3 is accompanied by the loss of stoichiometry at slightly higher Twb.