Synthesis and structural characterization of uranium-doped Ca2CuO3, a 1D   quantum antiferromagnet
  The technological settings of a modified sol-gel method for preparation of highly fine homogeneous powder Ca2CuO3 doped with uranium 238 (x=0-0.05) is presented. The analysis of structure, purity of phases and the justification for the role of uranium in the given compounds are provided together with almost complete classification of observed optical phonons by means of the Raman, IR measurements and ab initio calculation. The significant reduction in particle size was achieved by doping and the strong correlation between resistivity and doping concentration was observed and explained using the phonon-assisted electron hopping conduction model. The persistence of covalent insulation state in all compounds is a key feature of this class of compounds. 
Nam Nhat Hoang, Dang Chinh Huynh, Duc Tho Nguyen, Thuy Trang Nguyen,   Duc The Ngo, Michael Finnie, and Chau Nguyen