Crystal structural behavior of CoCu2O3 at high temperatures

Abstract

High temperature structure of CoCu2O3 The spin ladder compounds have received much attention recently due to their relation to the high transition temperature superconductivity. Also the study of spin ladder compounds is of great interest to explore the specific characteristics that result in their behavior. The CoCu2O3 spin ladder crystal structure is similar to SrCu2O3, which is apparent composition for many high temperature superconductors. The effects of temperature on structural change are investigated for this system. High temperature x-ray diffraction patterns were collected up to 10000C and the variation of lattice parameters as a function of temperature up to decomposition is studied. The thermal stability of CoCu2O3, has been studied at elevated oxygen pressures beyond a high temperature of 10000C [1]. Temperatures at which CoCu2O3 undergoes decomposition reactions were studied along with the products of the reactions. The study introduced here provides structural details and the linear coefficient of thermal expansion (CTE) before progressive decomposition. Experimental Details: Sample Preparation: Powder samples of (Ca1-xCox)Cu2O3 (x=0.05) were prepared by the solid state reaction method as described elsewhere [2]. The phase purity of the sample was verified by powder XRD measurements on polycrystalline samples and found to be in single phase. The chemical compositions of the synthesized samples were determined [2]. High Temperature X-Ray Diffraction: A circular corundum sample stage was loaded with fine powdered CoCu2O3 and loaded into the vacuumed high temperature stage in the Bruker D8 Advance X-Ray Diffractometer (Figure 1). Sample was heated at a rate of 0.50C/sec from 300C to 4000C. XRD data was collected at temperatures of 30 0 C, 100 0 C, 200 0 C, 300 0 C, and 400 0 C, then cooled at a rate of 1 0C/sec back to 30 0C for a final collection of data. Another run from 30 0C to 1000 0C was conducted to track the decomposition of the sample. XRD data was collected starting at 30 0C, and every 200 0C up to 1000 0C, and back to 30 0C. TOPAS was used to analyze the x-ray diffraction patterns and the track percent compositions of the sample at various temperatures. Origin8 was used to analyze the data and obtain the linear coefficient of thermal expansion. 30 40 50 60 70

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