In this work, microwave dielectric properties of A-site substitution by La 3+ in (Pb_ 0.45Ca_ 0.55)(Fe_ 0.5Nb_ 0.5)O_3 system were investigated. Microwave dielectric properties of A-site charge unbalance substitution ...In this work, microwave dielectric properties of A-site substitution by La 3+ in (Pb_ 0.45Ca_ 0.55)(Fe_ 0.5Nb_ 0.5)O_3 system were investigated. Microwave dielectric properties of A-site charge unbalance substitution of [(Pb_ 0.45Ca_ 0.55)_ 1-xLa_x](Fe_ 0.5Nb_ 0.5)O 3+ (P45CLFN) were improved because the solid solution of small amount of surplus La 3+ with (Pb,Ca) 2+ could eliminate oxygen vacancies, and the formation of secondary phase(pyrochlore) was also caused by surplus La 3+. The decreasing of dielectric constant with the increase of La 3+ content is due to the formation of pyrochlore. The grain size is changed slightly and Q_f values(7000～7300 GHz) are almost unchanged at x=0.02～0.10, but the temperature coefficient of resonant frequency (TCF) are increased and changed from negative to positive. TCF is zero at x=0075 with Q_f=7267 GHz and K=89. TCF of all specimens are within ±5×10 -6 ℃ -1.展开更多
This work investigated the microwave dielectric properties of A-site substitution by rare earth La3＋in（Pb0.5Ca0.5）（Fe0.5Ta0.5）O3（PCFT） system.A single perovskite phase was obtained only when the doping content ...This work investigated the microwave dielectric properties of A-site substitution by rare earth La3＋in（Pb0.5Ca0.5）（Fe0.5Ta0.5）O3（PCFT） system.A single perovskite phase was obtained only when the doping content was 2%.Suitable La3＋ doping improved microwave dielectric performances.Excessive La3＋doping caused the formation of secondary phase,which resulted in the decreasing of permittivity εrand quality factor Qfvalues.Especially,when the doping content is 2%-5%,permittivity εrwas above 75 and Qfvalues were 6 902-7 416 GHz.展开更多
文摘In this work, microwave dielectric properties of A-site substitution by La 3+ in (Pb_ 0.45Ca_ 0.55)(Fe_ 0.5Nb_ 0.5)O_3 system were investigated. Microwave dielectric properties of A-site charge unbalance substitution of [(Pb_ 0.45Ca_ 0.55)_ 1-xLa_x](Fe_ 0.5Nb_ 0.5)O 3+ (P45CLFN) were improved because the solid solution of small amount of surplus La 3+ with (Pb,Ca) 2+ could eliminate oxygen vacancies, and the formation of secondary phase(pyrochlore) was also caused by surplus La 3+. The decreasing of dielectric constant with the increase of La 3+ content is due to the formation of pyrochlore. The grain size is changed slightly and Q_f values(7000～7300 GHz) are almost unchanged at x=0.02～0.10, but the temperature coefficient of resonant frequency (TCF) are increased and changed from negative to positive. TCF is zero at x=0075 with Q_f=7267 GHz and K=89. TCF of all specimens are within ±5×10 -6 ℃ -1.
基金Project supported by the National Natural Science Foundation of China (Grant No.60578041)the National High Technology Research and Development Program of China (Grant No.715-006-0060)
文摘This work investigated the microwave dielectric properties of A-site substitution by rare earth La3＋in（Pb0.5Ca0.5）（Fe0.5Ta0.5）O3（PCFT） system.A single perovskite phase was obtained only when the doping content was 2%.Suitable La3＋ doping improved microwave dielectric performances.Excessive La3＋doping caused the formation of secondary phase,which resulted in the decreasing of permittivity εrand quality factor Qfvalues.Especially,when the doping content is 2%-5%,permittivity εrwas above 75 and Qfvalues were 6 902-7 416 GHz.
