Investigation of the Nd2O3-Lu2O3-Sc2O3 phase diagram for the preparation of perovskite-type mixed crystals NdLu1-xScxO3

Based on differential thermal analysis (DTA) and X-ray powder diffraction (XRD), a description of the Nd2O3-Lu2O3-Sc2O3 system was obtained by thermodynamic assessment. Four fields of primary crystallization could be identified; from melt compositions close to the Lu2O3-Sc2O3 edge, the rare-earth oxide C-phase crystallizes first which is stable down to room temperature. From Nd2O3 rich melts, the X-phase forms which is stable only at high temperatures. An additional field, where the alternative high-temperature phase H solidifies as primary product touches the Nd2O3-Lu2O3 edge of the concentration triangle. From melts close to the composition NdScO3, the P-phase (perovskite) can be crystallized and mixed crystals with second endmember NdLuO3 have been grown from the melt. Crystals of this mixed perovskite were grown by the micro-pulling-down and Czochralski methods.