HIGH-TEMPERATURE X-RAY-DIFFRACTION STUDY ON STABILITY OF THE INFINITE-LAYER SRCUO2

The stability of the infinite-layer SrCuO2 upon heating in air has been investigated by high-temperature X-ray diffraction. Above 300 degrees C the infinite-layer SrCuO2 reacted gradually with CO2 in air to form SrCO3; at a temperature over 400 degrees C, the infinite-layer SrCuO2 transformed into orthorhombic SrCuO2, with an abrupt decrease of the amount of the infinite-layer phase in the sample. The lattice parameters a and c of the infinite-layer SrCuO2 showed different thermal expansion coefficients, i.e,, da/dT = 3.329 x 10(-5) and dc/dT = 5.801 x 10(-5) Angstrom/degrees C. (C) 1994 Academic Press, Inc.