Crystal structure, oxygen stoichiometry and superconducting properties of GdBa2−xSrxCu3O7−δ (0.0 ≤ x ≤ 1.6)

✍ Scribed by R.A. Gunasekaran; B. Hellebrand; P.L. Steger

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 710 KB
• Volume: 270
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(96)00473-x

✦ Synopsis

The dependence of crystal structure, oxygen content and T c of ceramic GdBa 2_ xSr~Cu307 ,s (0.0 < x _< 1.6) samples on three different sets of annealing conditions was investigated. For samples annealed in oxygen at 900°C, a decrease of T c and orthorhombicity was observed with increasing Sr content. However, either annealing these samples in argon at, or quenching in air from 900°C, prior to annealing in oxygen at 500°C, leads to an enhancement of T c and orthorhombicity for 0 < x < 1.6. The oxygen non-stoichiometry (6) varied in the range 0 < ~ < 0.12 for all the samples. The AC susceptibility as a function of temperature and DC bias field was studied for some selected samples. The irreversibility line was determined for x = 0.0 and 1.0 samples annealed under three different conditions. Further, for the x = 1.0 sample, the influence of annealing at different temperatures in oxygen on the structure, oxygen content and T c was studied. The present study showed that substitution of Ba by Sr leads to a complex order-disorder behavior of the oxygen sub-lattice, depending on the annealing conditions.