High-pressure and-temperature synthesis and characterization of mixed valence perovskite oxides LaTi1-xMgxO3

Perovskite oxides LaTi1-xMgxO3 (x = 0.25, 0.5) were synthesized using high- pressure and-temperature method. LaTi0.75Mg0.25O3 is a new compound. This n ew synthesis route has some advantages. XRD analysis showed that the x = 0. 25 sample belongs to cubic perovskite-type structure and the a = 0.5 sample belongs to orthorhombic perovskite-type structure. EPR measurement indicat ed that Ti ions were in mixed valence state of +3 and +4. IR measurement in dicated that the vibration frequency and width of BO6 octahedron stretching vibration absorption band decreases with the increasing of x. The valence state of Ti ions can be altered by high-pressure and-temperature. (C) 2000 Elsevier Science S.A. All rights reserved.