Dielectric properties of Ba3Sr2DyTi3V7O30 ceramics

A polycrystalline sample, Ba 3 Sr 2 DyTi 3 V 7 O 30 , with tungsten bronze structure was prepared by a mixed-oxide method at high temperature (950°C). Preliminary structural analysis of the compound showed an orthorhombic crystal structure at room temperature. Surface morphology of the compound was studied by scanning electron microscopy. The dielectric anomaly at 321°C may be attributed to the ferro-paraelectric phase transitions. This was also confirmed from the appearance of a hysteresis loop. The nature of variation of the ac conductivity and value of activation energy at different temperature regions, suggest that the conduction process is of mixed-type ( i.e. , ionic-polaronic and space charge generated from the oxygen ion vacancies).