High-Temperature Structural Phase Transition in Ca0.7Ti0.7La0.3Al0.3O3: Investigation by Synchrotron X-Ray Diffraction |
| |
| Authors: | Guttamindapalli A Ravi Feridoon Azough Robert Freer Robert J Cernik Anthony M T Bell |
| |
| Affiliation: | Materials Science Centre, School of Materials, University of Manchester, Manchester M1 7HS, U.K.
;Daresbury Laboratory, Warrington WA4 4AD, U.K. |
| |
| Abstract: | Mixed-oxide prepared Ca0.7Ti0.7La0.3Al0.3O3 (CTLA) ceramics (≈96% dense), grain size 6–7 μm, with dielectric properties (at 4 GHz) of ɛr≈46, Q × f ≈38 000 GHz, and τf+13 ppm/°C, were studied at 25°–1300°C using synchrotron X-ray powder diffraction. At room temperature, CTLA exhibits a distorted orthorhombic structure, with two tilt systems: a =5.40383 (4) Å, b =5.41106 (6) Å, and c =7.64114 (7) Å with space group Pbnm . At 1050°±25°C, there is a transition from orthorhombic ( Pbnm ) to tetragonal ( I 4/ mcm ), with a simpler tilt arrangement. The lattice parameters at 1100°C were: a =5.44285 (4) Å and c =7.68913 (8) Å. |
| |
| Keywords: | |
|
|
