Papers by Author: Teruo Izumi

Abstract: Y_1-xGd_xBa₂Cu₃O_7-y film with BaZrO₃ was fabricated on CeO₂ buffered LaMnO₃/ion beam assisted deposition MgO/Gd₂Zr₂O₇/Hastelloy C276^TM substrates by the trifluoroacetates metal organic deposition process, whose microstructural and elemental analyses were performed by transmission electron microscopy. Y_1-xGd_xBa₂Cu₃O_7-y film with the thickness about 700 nm was found composed of c-axis oriented grains and large numbers of randomly oriented precipitates, such as (Y,Gd)₂Cu₂O₅, CuO and BaZrO₃. (Y,Gd)₂Cu²O⁵ and CuO precipitates were heterogeneously dispersed in the Y_1-xGd_xBa₂Cu₃O_7-y matrix with their sizes ranging between 100 and 200 nm, and BaZrO₃ precipitates were uniformly dispersed with their sizes ranging between 10 and 20 nm. Electron tomography with elemental information was performed further to reveal the three-dimensional information of BaZrO3 precipitates.

Abstract: In the present 5-year national project since 2003, the development of YBCO coated conductors (CC) has advanced rapidly. The high performance processing group of SRL-ISTEC and Fujikura Ltd. has been working on the long tape of the PLD-YBCO superconductor on the IBAD-Gd2Zr2O7 buffered substrate tape. Very recently the SRL group achieved the highest value on the product of Ic x L in the world, 51,940 Am (212 m x 245 A). Fujikura Ltd. also realized the longest buffered substrate tape of 500m long IBAD tape and obtained a 200 m long coated conductor with Ic value of 88 A. In the low cost processing group using MOD, CVD and so on, the high Ic value of 525 A was obtained by SRL using the TFA-MOD method on the IBAD substrate. The 45m long TFA-MOD tape was also obtained with the Ic value of 155 A by Showa Electric Wire and Cable Company. Similarly 100- 200 m class long tapes were also obtained by the MOCVD (Chubu Power Electric Company) and PLD-HoBCO processes (Sumitomo Electric Industry Ltd.). Both groups above are further developing for the final goal of 500 m long tapes with the Ic of 300 A/cm-w at the production rate of 5 m/h. Furthermore, the feasibility study for the application has started due to the above success of long tape production. Several kinds of preliminary experiments using long coated conductors are now in progress for the power applications such as (1) Power Cable, (2) Transformer, (3) Motor and so on.