Studies on the relaxor behavior of sol-gel derived Ba(Zr x Ti1− x )O3 (0.30≤x≤0.70) thin films
2006
Dixit, A. | Majumder, S. B. | Katiyar, R. S. | Bhalla, A. S.
We have studied the relaxor behavior of sol-gel derived Ba(Zr ₓ Ti₁₋ ₓ)O₃ (0.30≤ x≤0.70) thin films. The plausible mechanism of the relaxor behavior has been analyzed from the dielectric data and micro-Raman spectra. Substitution of Zr⁺⁴ for Ti⁺⁴ in BaTiO₃ lattice reduces its long-range polarization order yielding a diffused paraelectric to ferroelectric phase transition. The solid solution system is visualized as a mixture of Ti⁺⁴ rich polar region and Zr⁺⁴ rich regions and with the increase in Zr contents the volume fraction of the polar regions are progressively reduced. At about 25.0 at% Zr contents the polar regions exhibit typical relaxor behavior. The degree of relaxation increases with Zr content and maximizes at 40.0 at% Zr doped film. The frequency dependence of the polar regions follows Vogel-Fulcher relation with a characteristic cooperative freezing at freezing temperature (T f). Below Tf, a long range polarization ordering was ascertained from the polarization hysteresis measurement.
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