Uniaxial stress dependence of the dielectric properties of barium titanate single crystals |
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Authors: | J. Suchanicz D. Sitko |
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Affiliation: | 1. Institute of Technology, Pedagogical University, Krakow, Polandsfsuchan@up.krakow.pl;3. Institute of Physics, Pedagogical University, Krakow, Poland |
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Abstract: | BaTiO3 single crystals were grown by the melt-grown method. The effect of uniaxial pressure (0–1700 bar) on the dielectric properties of these crystals has been systematically studied. The external stress showed obvious effects on these properties. An increase in the difference between the Curie Tc and Curie–Weiss T0 temperatures induced by the applied pressure is observed. This could be ascribed to the inducing of non-ferroelectric cubic islands in the tetragonal phase by the applied compressive stress. On the other hand, the pressure behavior of thermal hysteresis and the ??/?T vs. T plot strongly suggests that the phase transition changes to second-order type with increasing pressure. The Curie–Weiss constant obtained from a modified Curie–Weiss law strongly decreases with increasing pressure, suggesting that the mechanism of phase transition is going to order–disorder type. An increase in the difference between the Curie Tc and Burn's TB temperatures with increasing pressure is observed. This could be ascribed to the narrowing of the temperature range on which the Curie–Weiss law is valid. In general, the obtained results are in good agreement with hydrostatic pressure data. Some kind of relaxation near Tc, which is strongly coupled with strain caused by applied compressive stress, is postulated. |
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Keywords: | single crystals uniaxial pressure dielectric properties barium titanate |
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