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
The structure-property relationships in Ba0.4Sr0.6Ti1-ySiyO3 with y=0.00,0.01,0.02,0.05,0.10 and 0.20 ceramics have been studied by using X-ray diffraction,electron microscopy and dielectric spectroscopy.An increase o...The structure-property relationships in Ba0.4Sr0.6Ti1-ySiyO3 with y=0.00,0.01,0.02,0.05,0.10 and 0.20 ceramics have been studied by using X-ray diffraction,electron microscopy and dielectric spectroscopy.An increase of Si concentration is not favorable for the stability of the perovskite structure,which results in the formation of BaTiSiO5 secondary phase.The dielectric peaks of samples are suppressed,broadened and shifted to low temperature with increasing Si concentration.Permittivity and Q value are reduced gradually with increasing Si concentration,due to growing of second BaTiSiO5 phase.The tunability(T) still remains ～18.0% under 60 kV/cm biasing for the samples with y-0.10.The best combination of microwave dielectric properties are obtained for the composition of y=0.10:-=531,Q=391(at 1.610 GHz) and T=17.7%.展开更多
Ba_(0.9)Sr_(0.1)TiO_(3) ceramics with or without ZnO have been prepared by traditional solid state reaction method.The XRD analysis showed that the doped Zn^(2+) ions diffused into the BST crystal lattice,resulting in...Ba_(0.9)Sr_(0.1)TiO_(3) ceramics with or without ZnO have been prepared by traditional solid state reaction method.The XRD analysis showed that the doped Zn^(2+) ions diffused into the BST crystal lattice,resulting in the variation of dielectric properties.Especially the dielectric constant at Curie point decreased with doping ZnO content when it is lower than 0.5 mol%.Due to the promotion of sintering,doping ZnO can enhance the density of ceramics but increase grain size.However,ZnO is a kind of semiconductor and can lead to the decrease in electrical breakdown strength value.展开更多
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.
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2009CB623302)
文摘The structure-property relationships in Ba0.4Sr0.6Ti1-ySiyO3 with y=0.00,0.01,0.02,0.05,0.10 and 0.20 ceramics have been studied by using X-ray diffraction,electron microscopy and dielectric spectroscopy.An increase of Si concentration is not favorable for the stability of the perovskite structure,which results in the formation of BaTiSiO5 secondary phase.The dielectric peaks of samples are suppressed,broadened and shifted to low temperature with increasing Si concentration.Permittivity and Q value are reduced gradually with increasing Si concentration,due to growing of second BaTiSiO5 phase.The tunability(T) still remains ～18.0% under 60 kV/cm biasing for the samples with y-0.10.The best combination of microwave dielectric properties are obtained for the composition of y=0.10:-=531,Q=391(at 1.610 GHz) and T=17.7%.
基金The work is supported by"Fundamental Research Funds for the Central Universities"(XDJK2016E010,XDJK2015C001 and SWU113054).
文摘Ba_(0.9)Sr_(0.1)TiO_(3) ceramics with or without ZnO have been prepared by traditional solid state reaction method.The XRD analysis showed that the doped Zn^(2+) ions diffused into the BST crystal lattice,resulting in the variation of dielectric properties.Especially the dielectric constant at Curie point decreased with doping ZnO content when it is lower than 0.5 mol%.Due to the promotion of sintering,doping ZnO can enhance the density of ceramics but increase grain size.However,ZnO is a kind of semiconductor and can lead to the decrease in electrical breakdown strength value.
