Anisotropy of thermal expansion in YAlO3 and NdGaO3 -: art. no. 251911

YAlO3 and NdGaO3 thermal expansion coefficients were measured using in situ powder x-ray diffraction in the temperature range of 28-650 degrees C. They exhibit a clear anisotropy: The expansion, quite similar along the [100] and [001] directions, is much lower along the [010] direction. The formation of cracks observed in YBa2Cu3O7-delta thin films deposited on YAlO3 and NdGaO3 substrates is likely related to the anisotropy. Stress value calculations have been performed in both systems. They indicate that the intrinsic components are specifically high in YAlO3. (c) 2005 American Institute of Physics.