Fluorine Doping Effect in the New Superconducting Y₃Ba₅Cu₈O_y Compound

K. Srinivasan, George Thomas C., P. Padaikathan

Department of Materials Engineering, Indian Institute of Science,Bangalore – 560 012, India.
Department of Physics, Christ University, Bangalore – 560 029, India.
Department of Physics, Govt. First Grade College, K. R. Puram,Bangalore – 560 036, India.

DOI: 10.4236/jmmce.2011.1014100                

Abstract

The newly identified yttrium based high critical temperature (Tc) superconductor of composition Y₃Ba₅Cu₈O_y (Y358) and the fluorine doped Y₃Ba₅Cu₈O_y-0.2F_0.2 (Y358+F) compounds were synthesized by solid state reaction technique. The micro structural and morphological features of the synthesized samples were investigated by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectrum (EDS) analysis. The XRD of the samples revealed a structure similar to Y₁Ba₂Cu₃O_y-o(Y123) compound with about three fold larger ‘c’ axis. The SEM image of the fluorine doped sample (Y358+F) showed a needle like inter growth which was different from that of pure (Y358) sample. The Tc of the sample, measured by self inductance method showed an onset of superconductivity at 92 K for the pure and 98 K for the fluorine doped sample. On further heating the fluorinated sample for 24 hours, the needle like intergrowth had disappeared as seen from SEM micrograph and the Tc onset of the sample had increased to 110 K with a two step transition.

Keywords

High Tc superconductor, solid state reaction, XRD, SEM, Tc measurement, fluorine doping.

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Bednorz JG, Muller KA, (1986) Z. Phys. B 64, 189-193.
[2]	Wu K, Ashburn JR, Torng CJ, Hor PH, Meng RL, Gao L, Huang ZJ, Wang YQ, Chu CW, (1987) Phys. Rev. Lett. 58, 908.
[3]	Marsh P, Fleming RM , Mandich ML, DeSantolo AM, Kwo J, Hong M, Martinez- Miranda LJ, (1988) Nature 334, 141-143.
[4]	Marezio M, Bordet P, Capponi JJ, Cava RJ, Chaillout C, Chenavas J, Hewat AW, Hewat EA, Hodeau JL, Strobel, (1989) Physica C. 162, 281-284.
[5]	Tavana A, Akhavan M, (2009) Eur. Phys. J. B. 469, 2010-2014.
[6]	Aliabadi A, Farshchi YA, Akhavan M, (2009) Physica C 469, 2012–2014.
[7]	Fisk Z, Thomson JO, Zirngiebl E, Smith JL, Cheong SW, (1987) Solid State Commun. 62, 743.
[8]	Horet PH, Meng RL, Wang YA, Gao L, Huang ZJ, Bechtold J, Forster K, Chu CW, (1987) Phys. Rev. Lett. 58, 1891.
[9]	Ovshinsky SR, Young RT, Allred DD, DeMaggio G, Vander Leeden GA, (1987) Phys. Rev. Lett. 58, 2579-2581.
[10]	Nakayama H, Fujita H, Nogami T, Shirota Y, (1988) Physica C. 936, 153-155.
[11]	Vanderah TA, Decker DL, Harris DC, Chamberland BL, (1989) Mat. Res. Bull. 24, 121.
[12]	Udomsamuthirun P, Kruaehong T, Nilkamjon T, Ratreng S, (2010) J. Supercond. Nov. Magn. 23, 1377.