Structural evolution and polar order inSr1−xBaxTiO3
| Autor: | C. Ménoret, Hichem Dammak, Olivier Hernandez, Jean Michel Kiat, Brahim Dkhil, M. Dunlop |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
010302 applied physics
Diffraction Phase transition Materials science Condensed matter physics chemistry.chemical_element Barium 02 engineering and technology Dielectric 021001 nanoscience & nanotechnology Polarization (waves) 01 natural sciences Ferroelectricity Condensed Matter::Materials Science Crystallography chemistry 0103 physical sciences Neutron 0210 nano-technology Phase diagram |
| Zdroj: | Physical Review B. 65 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.65.224104 |
| Popis: | We perform a combination of diffraction and diffusion of neutron and high-resolution x-ray experiments on the ${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{Ba}}_{x}{\mathrm{TiO}}_{3}$ system as well as dielectric susceptibility and polarization measurements. We show the ${\mathrm{SrTiO}}_{3}$-type antiferrodistortive phase up to a concentration of barium ${x}_{c}\ensuremath{\approx}0.094:$ the progressive substitution of Sr by Ba leads to a monotonic decrease and to a vanishing of the oxygen octahedra tilting. The critical concentration ${x}_{c}$ separates the phase diagram in two regions, one with a sole antiferrodistortive phase transition $(xl{x}_{c})$ and one with a succession of three ${\mathrm{BaTiO}}_{3}$-type ferroelectric phase transitions $(xg{x}_{c}).$ Inside the nonferroelectric antiferrodistortive phase a local polarization is observed, with a magnitude which is comparable to the values of the spontaneous polarization observed in the ferroelectric phases of the rich in barium-compounds. In these compounds a relative shift of Ti and Ba from the oxygen skeleton is measured and the spontaneous (long-range) polarization calculated from structural refinements. Its concentration and temperature evolution is in qualitative agreement with the values deduced from our dielectric susceptibility study. |
| Databáze: | OpenAIRE |
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