Effect Of CaO, CuO And V2O5 On Barium Zinc Tantalate (BZT) Dielectric Properties
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Date
2011-07
Authors
Jaafar, Hidayani
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Publisher
Universiti Sains Malaysia
Abstract
BZT has high dielectric constant (εr) and low dielectric loss (tan δ). However, the formation of BZT using solid state method required high sintering temperature to produce excellent dielectric properties. Therefore, to overcome these problems, other elements were added in BZT and investigate the effect of reducing sintering temperature of BZT by doping with by CaO, CuO and V2O5 respectively. CaO was selected as a doping compound because the Ca substitution form a new structured and avoid deteriorated dielectric properties in high frequency range. Meanwhile, adding CuO can avoid Zn evaporation problem which lower the dielectric properties. The selection of V2O5 as a doping compound is to improve BZT dielectric since V2O5 has a relatively low melting point. In this study, the experimental design is divided into three phases. In the first phase, the experiment was designed to produce the lowest calcination temperature that form single phase of BZT and 1150°C give the best result. For the second phase, BZT produced from the first phase was divided into; pure BZT sintered at 1350°C and doped BZT, (0.1 to 2.5 mol%) sintered at 1250°C. The samples produced were characterized using XRD, FESEM density and shrinkage analysis. In the third phase, the effects of dopants from second phase were investigated on dielectric properties of doped BZT. BZT + xCaO appeared to react to form BCZT and turn from hexagonal to cubic structure. While for BZT doped with CuO and V2O5, the structure remains unchanged. Increasing the mol% of dopants from 0.1 to 0.5 mol% produced more compacted structure. Each samples showed a resonance frequency from 10.3 to14.8 GHz and dielectric constants in the range of 26.29-75.9 and the dielectric loss is 0.04-0.159 depending on the mol% of dopant.
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Keywords
Effect of CaO, CuO and V2O5 , on barium zinc tantalate