Growth properties of Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7- delta / thin film on CeO/sub 2/(/MgO) buffer layer for the biepitaxial boundary function

In the fabrication of Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7- delta / (YBCO)/CeO/sub 2//MgO/SrTiO/sub 3//SrTiO/sub 3/ biepitaxial grain boundary junctions, the substrate temperature window for the growth of good quality superconducting YBCO overlayers on CeO/sub 2//MgO/SrTiO/sub 3/ is lower and narrower than for growth of YBCO on CeO/sub 2//SrTiO/sub 3/. Results of X-ray diffraction 2 theta and phi scan measurements reveal that the lattice structure of the CeO/sub 2/ layer on the MgO seed layer is 2 approximately 3 times more distorted than for CeO/sub 2/ on a bare SrTiO/sub 3/ substrate. It is found that the instability of the crystal formation of the YBCO layer on the CeO/sub 2//MgO/SrTiO/sub 3/ is accompanied by the loss of stoichiometry at slightly higher substrate temperature.<
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