High-pressure and high-temperature synthesis and characterization of mixed valence perovskite oxides LaTi_(1-x)Li_xO_3

摘要

Perovskite oxides LaTi_(1-x)Li_xO_3 (x=0.2, 1/3) were synthesized using high-pressure and high-temperature method. This new synthesis route has some advantages. XRD analysis showed that the x=0.2 sample belongs to cubic perovskite-type structure and the x= 1/3 sample belongs to orthorhombic perovskite-type structure. EPR measurement indicated that Ti ions were in mixed valence of +3 and +4. IR measurement indicated that the vibration frequency and width of BO_6 octahedron stretching vibration absorption band decreases with the increasing of x. Valence of Ti ions can be altered by high-pressure and high-temperature.