Superstructure and physical properties of skutterudite-related phase CoGe1.5Se1.5

17th IUMRS International Conference in Asia

Liang, Y.^1 ; Fang, B.^1 ; Zhu, X.M.^1 ; Liang, M.M.^1

Institute of Nuclear Technology and Application, School of Science, East China University of Science and Technology, Meilong Road 130, Shanghai

200237, China^1

关键词: Argon atmospheres;    Bulk samples;    Chemical compositions;    Hot-press techniques;    Increasing temperatures;    Phase purity;    Rhombohedral symmetry;    Type structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/182/1/012012/pdf
DOI  :  10.1088/1757-899X/182/1/012012

来源: IOP

【 摘 要 】

CoGe1.5Se1.5skutterudite-related phase with a homogeneity range has been synthesized by solid-state reaction. The phase purity, homogeneity range, crystal structure, thermal stability and electrical resistivity were studied. XRD data indicates that CoGe1.5Se1.5crystallized in a modification of the skutterudite CoAs3type structure with space group (a = b = 11.751(1) Å, c = 14.36(1) Å). HRTEM-SAED shows more information about the superstructure to confirm the rhombohedral symmetry with space group . The lattice parameter of this skutterudite-related phase was found to be dependent on the concentration of Ge and Se. CoGe1.5Se1.5decomposed between 1073 K and 1173 K under argon atmosphere investigated by in-situ XRD, suggesting a good thermal stability. CoGe1.49Se1.42, CoGe1.43Se1.34and CoGe1.50Se1.15dense bulk samples were obtained by hot-press technique. The chemical composition detected by FESEM/EDS suggests the homogeneity range and the existence of voids at framework positions. The electrical resistivity of the compounds decreases with increasing temperature, acting as a semiconductor. The chemical composition has a big influence on the value of electrical resistivity and energy gap.