Effects of Temperature Variation on Dielectric Properties of Ba₄(La_{(1 - z)}Bi_z)_9.33Ti₁₈O₅₄ Solid Solutions

Abstract

Bi modified Ba₄La_9.33Ti₁₈O₅₄ solid solutions were synthesized by conventional mixed oxide route. The three composition with molar formula Ba₄(La_{(1 - z)}Bi_z)_9.33Ti₁₈O₅₄ where z = 0.0, 0.1 and 0.2 were characterized for structural and dielectric properties. A detailed study related to variation in dielectric properties namely dielectric constant and dielectric loss with change in temperature from 298 K to 423 K was carried out in the frequency range 10 kHz–10 MHz. It was observed that dielectric constant decreases as the temperature increase from 298 K to 423 K in the entire frequency range for all the three samples. There was very small change in dielectric loss. The temperature coefficient of resonant frequency was estimated to improve from 273.8 ppm/K to 54.5 ppm/K as Bi contents increases from z = 0.0 to 0.2. Such materials would be a suitable candidate for applications in mobile communications.

Keywords:

• Ceramics
• dielectric constant
• dielectric loss
• temperature coefficient of resonant frequency

ACKNOWLEDGMENTS

The authors would like to thank Dr A. Banerjee, UGC-DAE CSR, Indore for providing the facility to study the dielectric properties as a function of temperature and frequency.