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Effect of Sulfur Doping on the Superconductivity of TlSr$_2$CuO$_z$ Cuprates
New Physics: Sae Mulli 2017; 67: 1048~1052
Published online September 29, 2017;
© 2017 New Physics: Sae Mulli.

Ho Keun LEE*, Jin KIM

Department of Physics, Kangwon National University, Chuncheon 24341, Korea
Correspondence to:
Received July 18, 2017; Revised July 25, 2017; Accepted July 25, 2017.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Polycrystalline samples of (Tl$_{1-x}$S$_x$) Sr$_2$CuO$_z$ with $0 \leq x \leq 0.7$ were synthesized by using a solid state-state reaction method. The phase formation and superconducting properties were investigated by means of X-ray diffraction and resistivity measurements. A superconducting transition behavior was observed in the S-doped samples with 0.1 $\leq x \leq$ 0.5 while the S-free pristine sample ($x$ = 0) showed no superconductivity down to 10 K. The superconducting transition behavior induced by the S-doping was accompanied by the formation of a new phase. We showed that the superconductivity induced by the S-doping was caused by the formation of a TlSr$_4$Cu$_2$SO$_4$O$_z$ oxysulphate phase with an onset $T_c$ of about 78 K. This new phase crystallized in the tetragonal system with $a$ = 3.852 Å and $c$ = 16.75 Å.
PACS numbers: 74.72.-h, 74.62.Dh, 74.62.Bf
Keywords: TlSr$_2$CuO$_z$, $S$-doping, oxysulphate, TlSr$_4$Cu$_2$SO$_4$O$_z$

September 2017, 67 (9)