Correlation Between Enhanced Tcand Unit Cell Volume in High-Tc Superconductor (Y1 − xEux)(SrBa)Cu3O6.94

Autor: I. Zorkani, A. El Kaaouachi, B. Bouallal, M. Bellioua, A. Taoufik, A. Nafidi, J. Hemine, H. Sahsah, Hassan Chaib, A. Toumanari
Rok vydání: 2008
Předmět:
Zdroj: Ferroelectrics. 372:93-99
ISSN: 1563-5112
0015-0193
DOI: 10.1080/00150190802382017
Popis: We report here on the preparation, X-ray diffraction with Rietveld refinement and AC susceptibility measurements of (Y1 − xEux)(SrBa)Cu3O6.94. We used two heat treatments: (i) the sintered sample was annealed in oxygen, this simple was denoted as [O] and (ii) the same sample was heated in argon, cooled and later annealed in oxygen [A,O]. When x increase from 0 to 1, the orthorhombicity ϵ = (b − a)/(b + a) decreases with Tc[O]. However, Tc[AO] decreases with ϵ until x = 0.2 and after it increases by 7 K to 87 K for x = 1 [A,O]. Note that the crystalline parameter b is constant but a (and c) increase indicating an increase of the number of oxygen atoms by chain (NOC) along a leading to a decrease of ϵ (Tc) [O] toward a tetragonal structure. It is possible that cationic disorder along c decreased for x ≥ 0.5. For each x, the [A,O] treatment increases ϵ (for 0 ≤ x ≤ 1), Tc (for x ≥ 0.5) and the distance d[Cu(1)-O1] (decrease Tc) for x 0.5. A remarkable correlation w...
Databáze: OpenAIRE