Glassy and ferroelectric aspects of potassium tantalate niobate
M D Fontana; M Maglione; U T Hochli; M D Fontana; Centre Lorrain d'Optique et Electron. des Solides, Univ. de Metz & Supelec, France; M Maglione; Centre Lorrain d'Optique et Electron. des Solides, Univ. de Metz & Supelec, France; U T Hochli; Centre Lorrain d'Optique et Electron. des Solides, Univ. de Metz & Supelec, France
Журнал:
Journal of Physics: Condensed Matter
Дата:
1993-03-22
Аннотация:
The dielectric susceptibility obtained for a crystal of KTaO<sub>0.96</sub>Nb<sub>0.04</sub>O<sub>3</sub> is presented as a function of temperature and frequency. The data are analysed in terms of parameters describing the relaxation strength and the width of the relaxation time distribution around an average value. The results are compared with those reported for KTa<sub>1-x</sub>Nb<sub>x</sub>O<sub>3</sub> crystals with lower niobium concentration (x=0, 0.0075 and 0.02). The degree of disorder introduced by niobium is thus described as function of niobium concentration. It is shown that the phase transition in KTaO<sub>0.96</sub>Nb<sub>0.04</sub>O<sub>3</sub> cannot be interpreted by the usual ferroelectric picture, nor by the glass-like behaviour.
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