Structure of La1.85Sr0.15CuO4 doped with Zn in high doping level

Practically impurity-free ceramic superconductors of La1.85Sr0.15Cu1-yZnyO4 with 0.00 less than or equal to y less than or equal to 0.30 were synthesized. The structure of these Zn-doped samples was characterized by X-ray diffraction studies. Rietveld refinements show that there is a tetragonal-to-orthorhombic phase transition which occurs at about y approximate to 0.15. The bond length between the two apical oxygen atoms in the CuO6 octahedra for the Zn-doped samples decreases with increasing content of Zn in the tetragonal region, and the tilt angle of the CuO6 octahedra increases with the content of Zn in the orthorhombic region. The metal-insulator transition is also observed in this Zn-doped systems.