Solid state reactions involving oxides of trivalent cations

Abstract

Selected mixtures in 69 binary systems involving Ab03, Ga20 a, CrZ0 3, Fe20 a, SczOa, In20 3, Y20 3, and the rare earth oxides were stud ied by X-ray diffraction techniques after heat treatment at various temperatures. A plot of the radii of the A +3 cations versus the radii of B+3 cations shows the regions of stability for the different structure types found for Ithe double oxides of the trivalent cations. The following structure types were encoun tered: A, B, and C-type rare earth oxide; corundum, beta gall ia; kappa alum ina; garnet; perovskite; and several types which could not be d efinite ly re lated to known structures. The majority of A+3 B+3 0 3 compounds have the perovskite structure. Several phases, including (1-x)Fez0 3·xAh03 ., and (1-x) Fe,03·xGa20 3 ." appear to have structures s imi lar to kappa alumina. Solid solution dcfin itely occurs in many of t he garnet type compounds which contain gailia. Based on the data collected in this survey, the s ubsolidu s phase equi libria re lationships of 79 binary systems were drawn.

Structural Study of La1–xYxScO3, Combining Neutron Diffraction, Solid-State NMR, and First-Principles DFT Calculations

“…[1][2][3][4][5][6][7] Many of these compounds exhibit interesting physical properties which have led to important fundamental and industrial applications. In particular, the LnScO 3 series has found application in ionic conductivity 8 and as a substrate for ferroelectric thin films.…”

Synthesis of Pr Heavily-Doped, Transparent YAG Ceramics.

“…It was nearly impossible, however, to fabricate a YAG single crystal doped with Pr element by the CZ method, because the effective segregation coefficient of the Pr was nearly zero, as reported by Monchamp. This difficulty might be due to the larger ionic radius of Pr3+ (0.116nm) than that of Y3+ (0.102nm).8) Schneider et al 8) reported that the ionic radii of the compositional elements must be limited to <0.106nm…”

Raman spectroscopy and lattice-dynamical calculations of Sc3CrO6single crystals

“…1 The mixed transition metal -rare earth oxides are interesting, because changing the temperature and pressure complex structural 8 and magnetic 9,10 phase diagrams can be observed. On the other side they were extensively studied because of their broad technological significance.…”

“…The mode with higher frequency is the in-phase vibration of the two octahedra, whereas the mode with lower frequency corresponds to the mode with out-of-phase vibration. The molecular approach predicts that the out-of-phase A g (ν 1 ) vibration has to be transformed into silent A 2g mode in R3c. Indeed, just the A g line at 668 cm −1 is one of the five lines with decreasing intensity.…”