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Sr0.5Ba0.5Nb2O6 (SBN50) with and without Cr2O3 dopant had been prepared by the solid-state reaction. The structural variations of undoped and Cr2O3-doped SBN were examined by the x-ray diffractometer. As the Cr2O3 content increases, the lattice parameters remain almost unchanged initially but become greatly changed revealing the increase in a axis and the decrease in c axis when the Cr2O3 content is >1 mol %, which was mainly influenced by the created oxygen vacancies. Isothermal sintering behavior of undoped and Cr2O3-doped SBN50 has been investigated. It was found that the creation of the charge-compensated oxygen vacancies and the accompanied structural change had a significant influence on the sintering behavior. The direct jumping path through vacant O sites (path 2 in Fig. 9) was further considered as the main reason for the enhancement of the densification rate and slight increase of the activation energy when the Cr2O3 content is <=1 mol % and the decrease of the densification rate but great increase of the activation energy when the Cr2O3 content is >1 mol %. Tmax [temperature at the maximum dielectric constant ([variant_greek_epsilon]max)] decreased with the increase of Cr doping and is essentially determined by the structural change of the NbO6 units in SBN. [variant_greek_epsilon]max is suggested to be determined by the competition between the reduction of the polarization due to the substitution of Cr for Nb and the enhancement of the polar moment arising from the weakening of Nb–O bonds due to the creation of the oxygen vacancies. [ABSTRACT FROM AUTHOR]

Sr0.5Ba0.5Nb2O6 (SBN50) with and without Cr2O3 dopant had been prepared by the solid-state reaction. The structural variations of undoped and Cr2O3-doped SBN were examined by the x-ray diffractometer. As the Cr2O3 content increases, the lattice parameters remain almost unchanged initially but become greatly changed revealing the increase in a axis and the decrease in c axis when the Cr2O3 content is >1 mol %, which was mainly influenced by the created oxygen vacancies. Isothermal sintering behavior of undoped and Cr2O3-doped SBN50 has been investigated. It was found that the creation of the charge-compensated oxygen vacancies and the accompanied structural change had a significant influence on the sintering behavior. The direct jumping path through vacant O sites (path 2 in Fig. 9) was further considered as the main reason for the enhancement of the densification rate and slight increase of the activation energy when the Cr2O3 content is <=1 mol % and the decrease of the densification rate but great increase of the activation energy when the Cr2O3 content is >1 mol %. Tmax [temperature at the maximum dielectric constant ([variant_greek_epsilon]max)] decreased with the increase of Cr doping and is essentially determined by the structural change of the NbO6 units in SBN. [variant_greek_epsilon]max is suggested to be determined by the competition between the reduction of the polarization due to the substitution of Cr for Nb and the enhancement of the polar moment arising from the weakening of Nb–O bonds due to the creation of the oxygen vacancies. [ABSTRACT FROM AUTHOR]

The structural variations of undoped and [Cr.sub.2][O.sub.3]-doped [Sr.sub.0.5][Ba.sub.0.5][Nb.sub.2][O.sub.6] (SBN) are investigated along with the isothermal sintering behavior by using the x-ray diffractometer. The maximum dielectric constant ([epsilon.sub.max]) is determined by the competition between the reduction of the polarization due to the substitution of Cr for Nb and the enhancement of the polar moment arising from the weakening of Nb-O bonds due to the creation of the oxygen vacancies.