Dielectric properties of bismuth doped Ba1−xSrxTiO3 ceramics

The dielectric properties of bismuth (5 at.%) doped Ba1−xSrxTiO3 (x=0, 0.2, 0.4, 0.6 and 0.8) ceramics are investigated. Bi doping significantly decreases the dielectric permittivity maximum of ferroelectric–paraelectric phase transition of Ba1−xSrxTiO3 solid solutions and shifts the ferroelectric–paraelectric phase transition temperature to lower temperatures for the x=0, 0.2, 0.4 and 0.6 compositions but to higher temperature for the x=0.8 composition. Bi doped BaTiO3 still exhibits normal ferroelectric characteristic while a relaxor behavior was observed in Bi doped Ba1−xSrxTiO3 and the degree of the diffuseness and the relaxation increases as x increases. A random electric field is suggested to be responsible for the relaxor behavior observations.