Effect of fluorine on superconducting properties of Ba-Y-Cu-O and Sr-Ba-Y-Cu-O systems

• Published in: Japanese Journal of Applied Physics Vol. 27; no. 7; pp. L1254 - L1256
• Main Authors: SUGISE, R, IHARA, H, YOKOYAMA, Y, OKUMURA, T, HIRABAYASHI, M, TERADA, N, JO, M, KOSHIZUKA, N, HAYASHIDA, I
• Format: Journal Article
• Language: English
• Published: Tokyo Japanese journal of applied physics 01.07.1988
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Properties of type I and type II superconductors; Superconductivity; Barium Copper Strontium Yttrium Fluorides oxides Mixed; Temperature; Electrical conductivity; Transition metal Compounds; Superconductivity; X ray; Experimental study; Lattice parameters; X ray diffraction; Barium Copper Yttrium Fluorides oxides Mixed; Inorganic compound; Chemical composition; Photoelectron emission; High temperature superconductor; Superconducting transition; Low temperature
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.27.L1254

Superconducting properties of Ba-Y-Cu-O-F and Sr-Ba-Y-Cu-O-F compounds were studied on the samples prepared by two different methods, a gas method and a powder method. The samples from the powder method showed superconductivity with a high T c above 90 K. The samples from the gas method, however, showed a semiconductive resistivity versus temperature and did not show superconductivity. The difference between lattice constants a and b decreased with increasing fluorine content, which indicated the fluorine occupation at the a -site. The XPS spectra of Ba and Cu core levels indicated that the cause of the deterioration of superconductivity was the doping with fluorine.