2003/11/25 by M. A. Ansari, V. P. S. Awana, Anurag Gupta +2
Physics and Astronomy · #cond-mat.supr-con #cond-mat.str-el
published as Proceedings NCMA-2004 · 4 pages including Figs, NCMA-2004, Dept. of Physics, Kurukshetra University, India
arxiv created 2003/11/25 · arxiv updated 2009/12/01
Samples of YBa2-xSrxCu3O7-d (x = 0.0, 0.50, 1.0) series were synthesized by solid-state reaction and first annealed in flowing O2 gas. All samples crystallized in orthorhombic structure, where orthorhombic distortion was found to decrease with an increase in x. Four probe resistivity measurements showed that superconducting transition temperature (Tc) decreases monotonically with x at a rate of dTc/dx = 1.3 K/at%. The sample with x=0 had a Tc = 91 K. The samples were further annealed in flowing N2 gas at 450 0C. The Tc of all samples decreased by nitrogen annealing. Interestingly, the decrease in Tc(x) became nearly three times larger at a rate of dTc/dx = 3.7 K/at%. The sample with x=0 had a Tc = 42 K. We discuss possible reasons and implications of the Tc(x) suppression vis stability of CuO chains. Key words: Y-123, Sr substitution, Superconducting transition