The effect of annealing time in oxygen flux on the electric properties of the Ru (Sr2-xCax)GdCu2O8±z system with 0.0 < x < 2.0, prepared at ambient pressure

• Published in: Physica. C, Superconductivity Vol. 424; no. 1-2; pp. 85 - 91
• Main Authors: ABATAL, M, CHAVIRA, E, FILIPPINI, C, GARCIA-VAZQUEZ, V, PEREZ, J. C, THOLENCE, J. L, NOËL, H
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 01.08.2005
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Properties of type I and type II superconductors; Superconductivity; Transport properties (electric and thermal conductivity, thermoelectric effects, etc.); Scanning electron microscopy; Annealing; Electrical conductivity; Ruthenium oxides; Controlled atmospheres; Differential thermal analysis; XRD; Nonstoichiometry; Gadolinium oxides; Calcium oxides; Strontium oxides; Multi-element compounds; Transmission electron microscopy; Synthesis; Solid state reaction; High-Tc superconductors; Electric resistivity; Semiconductivity; Chemical composition; SEM; Copper oxides; TEM
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2005.04.026

A solid-state reaction method for synthesis of Ru(Sr2-xCax)GdCu2O8+/-z system within the composition range of 0.0 < x < 2.0, at ambient pressure and within the range of 960-1070 deg C is reported. The temperature interval for the preparation of the solid solution is determined by differential thermal analysis (DTA) in air. A solid solution is shown to exist up to x=0.1, with a crystalline structure that is isomorphous to RuSr2GdCu2O8 (Ru-1212) compound observed by X-ray powder diffraction (XRD). The studies by the scanning electron microscopy (SEM) technique gives a particle size around 1-6mum. The results of transmission electron microscopy (TEM) studies confirm the tetragonal unit cell of Ru(Sr2-xCax)GdCu2O8+/-z system. The temperature dependence of the electrical resistivity of the samples annealed in oxygen flux for 12 and 41h, respectively at T=960 deg C shows a semiconductor behavior.