Microwave Dielectric Properties and Far Infrared Spectrum of <TEX>$(Pb_{1-x}Ca_x)(Fe_{0.5}Ta_{0.5})O_3$</TEX> Ceramics

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J. Korean Ceram. Soc. > Volume 37(3); 2000 > Article

Journal of the Korean Ceramic Society 2000;37(3): 256.

$(Pb_{1-x}Ca_x)(Fe_{0.5}Ta_{0.5})O_3$ 세라믹스의 마이크로파 유전특성 및 Far Infrared Spectrum

박흥수, 윤기현, 김응수¹

연세대학교 세라믹공학과
¹경기대학교 재료공학과

Microwave Dielectric Properties and Far Infrared Spectrum of $(Pb_{1-x}Ca_x)(Fe_{0.5}Ta_{0.5})O_3$ Ceramics

ABSTRACT

The dielectric properties of complex perovskite ($Pb_{1-x}Ca_{x}$)($Fe_{0.5}Ta_{0.5}$)$O_{3}$ with >($0.5{le}x{ge}0.65$ were investigated at microwave frequencies. Dilectric constant decreased with increasing Ca content, and was directly proportional to the cube of average ionic ra야 of A-site. For the specimen of x=0.6 sintered at $1250^{circ}C$ for 3 h in air, dielectric constant (k) of 63, QF of 11000 GHz, and the temperature coefficient of resonant frequency(TCF) of -14ppm/$^{circ}C$ were obtained. As Ca content increased, TCF of the specimen negatively increased due to the reduction of the tolerance factor(t). Changes in intrinsic loss with varying Ca content was investigated by the infrared reflectivity spectra ranging 50 to 4000 $cm^{-1}$, which were calculated by the Kramers-Kronig analysis and classical oscillator model. The relative tendency of microwave dielectric properties of the ($Pb_{1-x}Ca_{x}$)($Fe_{0.5}Ta_{0.5}$)$O_{3}$ specimens calculated from the reflectivity data were in good agreement with the results by the post resonant method.

Key words: $(Pb_{1-x}Ca_x)(Fe_{0.5}Ta_{0.5})O_3$, Infrared reflectivity spectra, Dispersion parameter, Tolerance factor