Influence of ionic radius of rare-earths on the structural and electrical properties of Ba5RTi3Nb7O30（R=rare-earth） ferroelectric ceramics
来源期刊：Journal of Rare Earths2015年第12期
论文作者：Prasun Ganguly
文章页码：1310 - 1315
摘 要：In the present report,Ba5RTi3Nb7O30（R=La,Nd,Sm,Eu,Dy） compounds were synthesized by solid-state reaction method in order to know the effect of ionic radius of rare-earths on their structural,dielectric,ferroelectric,pyroelectric,piezoelectric and conductive properties.X-ray diffraction analysis revealed the formation of the compounds having orthorhombic structure.Scanning electron micrographs showed the formation of fine granular microstructure in all the compounds with a decrease in the average grain size with increasing ionic radius of the substituted rare-earths.Detailed dielectric studies showed that the dielectric constant（ε’r） increased while Curie temperature（Tc） decreased as the ionic radius of the rare-earths increased.With the decrease in the ionic radius of the rare-earths,remanent polarization（2Pr）,piezoelectric(d33) and pyroelectric coefficients were observed to increase in Ba5RTi3Nb7O30 compounds.The temperature variation of dc conductivity suggested that the compounds had negative temperature coefficient of resistance（NTCR） behaviour.
Prasun Ganguly
摘 要：In the present report,Ba5RTi3Nb7O30（R=La,Nd,Sm,Eu,Dy） compounds were synthesized by solid-state reaction method in order to know the effect of ionic radius of rare-earths on their structural,dielectric,ferroelectric,pyroelectric,piezoelectric and conductive properties.X-ray diffraction analysis revealed the formation of the compounds having orthorhombic structure.Scanning electron micrographs showed the formation of fine granular microstructure in all the compounds with a decrease in the average grain size with increasing ionic radius of the substituted rare-earths.Detailed dielectric studies showed that the dielectric constant（ε’r） increased while Curie temperature（Tc） decreased as the ionic radius of the rare-earths increased.With the decrease in the ionic radius of the rare-earths,remanent polarization（2Pr）,piezoelectric(d33) and pyroelectric coefficients were observed to increase in Ba5RTi3Nb7O30 compounds.The temperature variation of dc conductivity suggested that the compounds had negative temperature coefficient of resistance（NTCR） behaviour.
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