The ternary system Gd2O3-SrO-CuO: compounds and phase relations

The subsolidus phase relations of the Gd2O3-SrO-CuO ternary system have bee n investigated by X-ray powder diffraction. All samples were synthesized in air at 950-1000 degreesC. The system can be divided into ten three-phase r egions and two solid solutions. In tills system, there exist two solid solu tions: Sr14-xGdxCu24Oy and Gd1-xSr2-xCu2Oy and one ternary compound: GdSr3C u2Oy The solid solution Sr14-xGdxCu24Oy (0 less than or equal tox less than or equal to6.5) crystallizes in an orthorhombic structure cell with space group Fmmm and lattice constants of a=3.918(1)-3.975(1) Angstrom, b=11.466( 3)-11.282(1) Angstrom and c=13.389(4)-12.832(1) Angstrom. The solid solutio n Gd1-xSr2-xCu2Oy (0 less than or equal tox less than or equal to0.3) belon gs to an orthorhombic system with space group Immm, lattice constants a=3.7 55(1)-3.763(1) Angstrom, b=11.354(4)-11.257(4) Angstrom and c=20.008(4)-20. 049(5) Angstrom. The ternary compound (Gd0.25Sr0.75)(2)CuO4-delta crystalli zes in an orthorhombic structure with space group Immm and lattice constant s of a=3.7084(3) Angstrom, b=3.7841(4) Angstrom and c=12.6129(9) Angstrom. (C) 2001 Elsevier Science B.V. All rights reserved.