Thermal Analysis of Rare Earth Gallates and Aluminates.

Dilatometry, high temperature x-ray diffraction, differential thermal analysis and differential scanning calorimetry have been performed on LaGaO sub 3, LaAlO sub 3, SmAlO sub 3, NdGaO sub 3, and PrGaO sub 3 single crystals. First order phase transitions have been located at 146C for LaGaO sub 3 and 785C for SmAlO sub 3 and delta H measured for the LaGaO sub 3 transition. Second order transitions have been identified for PrGaO sub 3, NdGaO sub 3, LaGaO sub 3 and LaAlO sub 3. The usefulness of these compounds as substrates for high temperature superconducting ceramics is discussed in terms of thermal expansion coefficient matching.