HIGH-TEMPERATURE CREEP OF THE PEROVSKITES CATIO3 AND NANBO3

We have performed a series of creep experiments on single crystals of the perovskites CaTiO3 and NaNbO3 at temperatures above 0.67 T(M). Both are found to deform according to a dislocation-controlled power-law mechanism. Experiments performed on CaTiO3 with the applied stress parallel to two different directions, indicate a strong dependence of creep rate on orientation. Comparison of these results with those of earlier studies on the perovskites BaTiO3, KTaO3 and KNbO3 indicates that materials with the perovskite structure do not be long to an 'isomechanical group' as defined by previous researchers.