Polycrystalline samples of (1 - x)Pb(Yb1/2Ta 1/2)O3-xPb(Fe1/2Ta1/2)O3 with x = 0.0, 0.1, 0.13, 0.15, 0.18 and 0.2 are prepared by solid state reaction method. The formation and structural changes are identified by X-ray diffraction studies. A uniform distribution of grains is observed from the microstructure by scanning electron microscopy. The dielectric measurement of the compounds is carried out at 1-200 kHz in the temperature range -100 to 300°C. The substitution of Fe3+ ion at Yb3+ sites of Pb(Yb1/2Ta1/2)O3 significantly enhances the dielectric constant value, increases the diffuseness in the mode of phase transition and lowers the transition temperature. A detailed analysis of the dielectric response of the compounds is given in conjecture with their structural data. © 2005 Elsevier B.V. All rights reserved.

Venkatachalam Subramanian

Department Of Physics

Krishnaswamy Hariharan

Data acquisition

Grain boundaries

microstructure

Permittivity

Phase Transitions

Scanning electron microscopy

X ray diffraction analysis

X ray spectroscopy

Dielectric response

DOPING EFFECT

SOLID STATE REACTION METHOD

Polycrystalline materials

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IIT Madras

Materials Science and Engineering B: Solid-State Materials for Advanced Technology

The structure and low frequency dielectric properties of Pb 1 - x Ba x (Yb 1/2 Ta 1/2 )O 3 solid solutions with x=0.00, 0.10, 0.15, 0.20 and 0.30 have been investigated usingX-raydiffraction and dielectric constant measurements. As Ba 2+ concentration increases beyond x=0.15, the crystal structure changes from monoclinic to pseudocubic at room temperature. The sharp paraelectric- antiferroelectric phase occuring in pure Pb(Yb 1/2 Ta 1/2 )O 3 , remarkably decreases and simultaneously the weak ferroelectric phase gets enhanced with increase in x. The maximum value of the dielectric constant (K max ) varies with x, showing a peak value at x=0.20 whereas dielectric maximum temperature (T max ) continuously decreases with increase in x. The diffuseness exponent and degree of diffuseness are calculated for x=0.15, 0.20 and 0.30 by fitting the dielectric data to the modified Curie-Weiss law and the values indicate that the compounds exhibit diffuse phase transition. The paper also discusses the influence of calcination and sintering temperature on the dielectric properties of pure Pb(Yb 1/2 Ta 1/2 )O 3.

Ferroelectrics

Dielectric study of the phase transitions in Pb1-xBa x(Yb1/2Ta1/2)O3 ceramics

Journal of the American Ceramic Society

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Japanese Journal of Applied Physics

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Principles and Applications of Ferroelectrics and Related Materials

Journal of the European Ceramic Society

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Microtructure and dielectric properties of (1 - X)Pb(Yb 1/2Ta1/2)O3-xPb(Fe1/2Ta 1/2)O3, 0 ≤ x ≤ 0.2 solid solution ceramics

Journal	Materials Science and Engineering B: Solid-State Materials for Advanced Technology
ISSN	09215107
Open Access	No