Effect of Ba5Ta4O15 on microstructural characteristics of Ba(Mg1/3Ta2/3)O3 ceramics and their microwave dielectric properties

Microstructures of the Ba(Mg13Ta23)O3, BMT, materials were examined using transmission electron microscopy. It is observed that small BMT grains usually contain very few defects, whereas large BMT grains always contain large proportion of dislocations, stacking faults and midribs of secondary phase. Incorporation of small amount (∼0.1 mol%) of Ba5Ta4O15 particles improves the uniformity of grains. However, the density of dislocations increases tremendously, resulting in tangling of dislocations and even the formation of networks, whereas the proportion of stacking faults decreases pronouncedly for the Ba5Ta4O15 added BMT materials. Presumably, it is through the hindrance on the growth of grains and modification on the formation of defects that incorporation of Ba5Ta4O15 particles alters the microwave dielectric properties of BMT materials.