Study of barrier layer capacitance effect in lead free Ba_(0.95)Sr_(0.05)(Fe_(0.5)Nb_(0.5))O3-BaZr_(0.1)Ti_(0.9)O_3 ceramics

摘要

Lead-free Ba_(0.95)Sr_(0.05)(Fe_(0.5)Nb_(0.5))O_3-BaZr_(0.1)Ti_(0.9)O_3 (50/50) ceramic, a material with potential applications for energy storage, are investigated. X-ray diffraction patterns show a single phase perovskite structure in all the samples. Sintering temperature affects the micro structural and dielectric properties of the ceramics. Microstructural analysis showed the uniformly distributed and highly packed grains in all the samples. We obtained high dielectric constant with low dielectric loss due to the controlled sintering. Giant dielectric constant (~19496) with low dielectric loss (?0,32) was obtained for 1250 °C sintered sample at room temperature and 1 kHz frequency. Complex impedance analysis confirms that the grain boundary effect (barrier layer formation) is responsible for such a high value of dielectric constant. Another interesting feature of this ceramic is the appearance of room temperature magnetodielectric response (1.9%, 8 kOe) at 100 Hz frequency.