Nucleation of YBa(sub 2)Cu(sub 3)O(sub 7(minus)(Delta)) in the BaF(sub 2) Process.

Wu, L. ; Solovyov, V. F. ; Wiesmann, H. J. ; Zhu, Y. ; Suenaga, M.

Technical Information Center Oak Ridge Tennessee

关键词: Nucleation;    Electron microscopy;    X-ray diffraction;    Quenching;    Annealing;   

RP-ID  :  DE2001781369

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The nucleation of the c-axis aligned and non-c-axis Yba(sub 2)Cu(sub 3)O(sub 7(minus)(delta)) (YBCO) from precursor films on (001)-cut SrTi(sub 3) was investigated for the so-called BaF(sub 2) process. Specimens with different thickness were quenched from 735 deg C, then studied by transmission electron microscopy and x-ray diffraction techniques. Preceding the formation of YBCO nuclei, three intermediate phases of (Y,Ba) oxy-fluoride and a transition phase without F were found in the precursor films. These were structurally and chemically related to the nuclei of YBCO which was found to be deficient in Cu relative to its stoichiometric composition.