The ac impedance of Nb-doped semicon-ducting (Bao.72Pbo.28)TiO3 ceramics implanted with copper ions(200keV,6X1015 and 1X1017 ions/cm2) in the temperature range 25-320C and the frequency range 10 Hz -13MHz was measured...The ac impedance of Nb-doped semicon-ducting (Bao.72Pbo.28)TiO3 ceramics implanted with copper ions(200keV,6X1015 and 1X1017 ions/cm2) in the temperature range 25-320C and the frequency range 10 Hz -13MHz was measured. According to the change of impedance spectroscopy and the equivalent circuit model of semiconducting(Ba, Pb)TiO3 ceramics, the dependence of resistance of bulk and grain-boundary on temperature was analyzed. The results show that relatively low dose must be used to increase the magnitude of the positive temperature coeffieient of resistance(PTCR)effects in the cermmics. In addition,the effects of Cu ion implantation on the PTCR behavior of the ceramics was studied by raststance-tempera-ture measurement.展开更多
High-performance dielectric tunable materials with both high dielectric tunability and low dielectric loss are urgently needed for new-generation electronic tunable devices.In the present study,a new system,(Ba_(0.675...High-performance dielectric tunable materials with both high dielectric tunability and low dielectric loss are urgently needed for new-generation electronic tunable devices.In the present study,a new system,(Ba_(0.675)Sr_(0.325))_(1−x)La_(x)Ti_(1−x)MnxO_(3)(x=0.25%,0.5%,0.75%,and 1.0%),was designed.The acceptor dopant Mn was added to lower dielectric loss,while the donor dopant La was introduced to enhance dielectric tunability.The samples were prepared using the conventional solid-state(CS)reaction method and the semi-solution(SS)method.The experimental results showed that the morphology of the ceramics was optimized by further improving the processing procedure.Dense microstructures,homogeneous grains,and uniform dopant distributions could be achieved successfully by the semi-solution method.Moreover,a significant enhancement in the tunable properties was realized owing to the improved microstructure mentioned above.The optimum tunable properties occurred in the samples prepared by the semi-solution method at x=0.75%,with a high dielectric tunability of 85.0%,a low dielectric loss of 0.0011,and an excellent figure of merit(FOM)of 773.The tunable properties of(Ba,Sr)TiO_(3)(BST)ceramics were even superior to those of lead-based materials,with an FOM of approximately 700.All the results suggested that the semi-solution method rendered BST ceramics more promising for applications in tunable devices.展开更多
文摘The ac impedance of Nb-doped semicon-ducting (Bao.72Pbo.28)TiO3 ceramics implanted with copper ions(200keV,6X1015 and 1X1017 ions/cm2) in the temperature range 25-320C and the frequency range 10 Hz -13MHz was measured. According to the change of impedance spectroscopy and the equivalent circuit model of semiconducting(Ba, Pb)TiO3 ceramics, the dependence of resistance of bulk and grain-boundary on temperature was analyzed. The results show that relatively low dose must be used to increase the magnitude of the positive temperature coeffieient of resistance(PTCR)effects in the cermmics. In addition,the effects of Cu ion implantation on the PTCR behavior of the ceramics was studied by raststance-tempera-ture measurement.
基金supported by the National Natural Science Foundation of China(No.U1966602).
文摘High-performance dielectric tunable materials with both high dielectric tunability and low dielectric loss are urgently needed for new-generation electronic tunable devices.In the present study,a new system,(Ba_(0.675)Sr_(0.325))_(1−x)La_(x)Ti_(1−x)MnxO_(3)(x=0.25%,0.5%,0.75%,and 1.0%),was designed.The acceptor dopant Mn was added to lower dielectric loss,while the donor dopant La was introduced to enhance dielectric tunability.The samples were prepared using the conventional solid-state(CS)reaction method and the semi-solution(SS)method.The experimental results showed that the morphology of the ceramics was optimized by further improving the processing procedure.Dense microstructures,homogeneous grains,and uniform dopant distributions could be achieved successfully by the semi-solution method.Moreover,a significant enhancement in the tunable properties was realized owing to the improved microstructure mentioned above.The optimum tunable properties occurred in the samples prepared by the semi-solution method at x=0.75%,with a high dielectric tunability of 85.0%,a low dielectric loss of 0.0011,and an excellent figure of merit(FOM)of 773.The tunable properties of(Ba,Sr)TiO_(3)(BST)ceramics were even superior to those of lead-based materials,with an FOM of approximately 700.All the results suggested that the semi-solution method rendered BST ceramics more promising for applications in tunable devices.
