Thermoelastic anisotropy in NdScO3 and NdGaO3 perovskites

Single crystal thermal expansion and elastic stiffness of NdGaO3 and NdScO3 were investigated by inductive gauge dilatometry and resonant ultrasound spectroscopy between 103K and 1673K, as they are used extensively as perovskite-type substrates for epitaxial crystal growth. Thermal expansion of NdGaO3 is in agreement with literature data and has very similar magnitude and anisotropy compared to NdScO3. The anisotropy of the elastic stiffness of NdGaO3 is more pronounced and qualitatively different from what is found for NdScO3. It is explained in terms of structural instabilities, which lead to known phase transitions in other perovskites. The anisotropy of the elastic stiffness of NdGaO3 is compatible with what is found for other orthorhombic perovskites that undergo a transition to a rhombohedral structure at high temperatures. The elastic properties of NdScO3 directly follow from the properties of other REScO3. The samples were characterized with regards to their compositions and lattice parameters using electron probe microanalysis and X-ray powder diffraction. [Display omitted] •Thermal expansion of NdGaO3 and NdScO3 was investigated from 103 K to 1673 K.•Elastic properties of NdGaO3 and NdScO3 were investigated from 103 K to 1673 K.•Anisotropies reflect structural symmetry generated by potential phase transitions.•Elastic properties of NdGaO3 do not depend on crystal grower.