The effect of lattice matching between buffer layer and YBa/sub 2/Cu/sub 3/O/sub 7-δ/ thin film on in-plane alignment of c-axis oriented thin films

Crystallinity and surface morphology of YBCO thin films using an amorphous buffer layer deposited at a low temperature

“…The dispersion of the in-plane crystallographic axis of YBCO films on well-crystalline buffer layers is smaller than that for YBCO films grown on bare MgO substrates. The mean value of YBCO films on SrSnO buffer layer on an MgO substrate is 1.26 , and the dispersion of the in-plane crystallographic axis of YBCO films with SrSnO buffer layer is smaller than that for YBCO films with a buffer layer [1]. The crystallinity of YBCO films with and without buffer layers are shown in Table I.…”

“…The -axis dispersion of YBCO films on well-crystalline buffer layers is smaller than that of YBCO films on bare MgO substrates. The FWHM value of YBCO films on SrSnO buffer layer over the MgO substrate is about 0.6 , and -axis dispersion of YBCO films with YBCO buffer layer is smaller than for YBCO films deposited on a SrSnO buffer layer [1]. The -axis length of a YBCO film grown on a buffer layer annealed at 950 C, estimated using values from (002) to (0013) plane, is 11.730 .…”

“…However, there is a lattice mismatch between MgO and YBCO, and YBCO films on MgO substrates have two kinds of in-plane oriented grains. Therefore, YBCO films are usually deposited on a buffer layer such as BaSnO , SrSnO and BaZnO [1]. We found that YBCO films deposited on bare MgO substrates at a temperature of 650 C, which have good superconducting properties, don't have good crystallinity.…”

High-speed operation of quasi-one junction superconducting quantum interference device based on high-Tc multilayer technology

“…Because of the lower deposition temperatures used to obtain c-axis YbBCO or La-YbBCO thin films than for YBCO, IEJs with relatively low I c suitable for SFQ circuits can be easily fabricated without degrading the sheet inductance. 13,14 As for the insulating layers, cubic perovskite SrSnO 3 , with a lattice constant slightly larger than that of YBCO, 9,15 was used. We confirmed that use of 360-nm-thick SrSnO 3 sputtered at 680°C in 44 mTorr Arϩ50 vol % O 2 gas was effective to reproducibly obtain multilayers with average surface roughness of less than 2 nm and interlayer resistivity above 1 G⍀ cm.…”

Hetero-Epitaxial Growth of CeO2 Films on MgO Substrates

“…This phenomenon is the same as the self-epitaxy of CeO 2 thick films for coated conductors. 10) We have been growing several films on MgO substrates, such as BaSnO 3 , 11) BaZrO 3 , 12) SrSnO 3 , 13) and CaSnO 3 13) films. Typical rocking curves (!)…”