In this work,dense CdCu_(3)(Al_(l/2)Ta_(l/2))xTi_(4)-xO_(12)ceramics were prepared by a conventional solid phase method.The effect of Al3+/Ta5+dopants on the dielectric properties of CdCu_(3)Ti_(4)O_(12)ceramics was s...In this work,dense CdCu_(3)(Al_(l/2)Ta_(l/2))xTi_(4)-xO_(12)ceramics were prepared by a conventional solid phase method.The effect of Al3+/Ta5+dopants on the dielectric properties of CdCu_(3)Ti_(4)O_(12)ceramics was systematically investigated.Upon Al^(3+)/Ta^(5+)co-doping,the dielectric properties of CdCu_(3)(Al_(l/2)Ta_(l/2))_(x)Ti_(4-x)O_(12)were significantly enhanced.Particularly,the CdCu_(3)(Al_(l/2)Ta_(l/2))_(0.05)Ti_(3.95)O_(12)material displays a decent dielectric property,where dielectric constants(εr,~27181),loss tangent(tanð~0.069)at a test frequency of 1 kHz are able to satisfy the application temperature requirement of the Y6R capacitor.Surprisingly,the refined grains resulting from Al^(3+)/Ta^(5+)co-doping lead to heightened resistance at grain boundaries,which is closely associated with enhanced dielectric prop-erties.Meanwhile,the giant dielectric property of the materials can be attributed to the effect of the intemal barrier layer capacitance.The obtained results are expected to provide a new idea for obtaining high dielectric constant and low loss tangent in CdCTO-based materials and promote the practical application of such materials.展开更多
Colossal permittivity(CP)materials,particularly co-doped TiO_(2) ceramics,have garnered significant attention for their potential in high-performance ceramic capacitors.However,understanding the origin of CP remains a...Colossal permittivity(CP)materials,particularly co-doped TiO_(2) ceramics,have garnered significant attention for their potential in high-performance ceramic capacitors.However,understanding the origin of CP remains a challenge,with the role of doping ratios between acceptor and donor ions largely underexplored.This study addresses this gap by systematically investigating the effects of Ga^(3+)concentrations on the microstructure and CP of Ga_(y)Nb_(0.025)Ti_(0.975-y)O_(2),prepared via the solid-state reaction method.The sintered ceramics exhibited a dense rutile TiO_(2) phase with increasing grain sizes and oxygen vacancies.Notably,CP values as high as 10^(5) were achieved at Ga^(3+)/Nb^(5+)ratio<1.0.Optimal dielectric properties were observed at Ga^(3+)/Nb^(5+)=1.0,yielding a CP of 6.4×10^(4) and a loss tangent<0.03,surpassing the performance of many existing CP materials.Impedance spectroscopy revealed distinct electrical heterogeneity,with conductive grains and highly resistive grain boundaries with activation energies>1.0 eV.Ceramics with 5%Ga^(3+) doping showed diminished CP due to the absence of semiconducting grains.The findings suggest that CP originates from the internal barrier layer capacitor.This study not only elucidates the crucial role of doping ratios in tailoring CP but also establishes a pathway for developing advanced dielectric materials with superior performance for ceramic capacitors.展开更多
This paper reports on synthesis of polycrystalline complex perovskite CaCu_(3)Ti_(4)O_(12)(as CCTO)ceramic powders prepared by a sol–gel auto combustion method at different sintering temperatures and sintering times,...This paper reports on synthesis of polycrystalline complex perovskite CaCu_(3)Ti_(4)O_(12)(as CCTO)ceramic powders prepared by a sol–gel auto combustion method at different sintering temperatures and sintering times,respectively.The effect of sintering time on the structure,morphology,dielectric and electrical properties of CCTO ceramics is investigated.Tuning the electrical properties via different sintering times is demonstrated for ceramic samples.X-ray diffraction(XRD)studies confirm perovskite-like structure at room temperature.Abnormal grain growth is observed for ceramic samples.Giant dielectric permittivity was realized for CCTO ceramics.High dielectric permittivity was attributed to the internal barrier layer capacitance(IBLC)model associated with the Maxwell–Wagner(MW)polarization mechanism.展开更多
基金supported by the National Science Foundation of China(NSFC)(Grant Nos.52202143 , 52272119)The authors would also like to thank the Young Talent Fund of University Association for Science and Technology in Shaanxi,China(20230415)+3 种基金the Fundamental Research Fundsfor the Central Universitiess(Grant No.GK202401009)the Excellent Graduate Training Program of Shaanxi Normal University(No.LHRCCX23223)Key Research and Development Program of Shaanxi Provincial Science and Technology Department(Grant No.2023-YBGY-162)the Fundamental Innovation Project in School of Materials Science and Engineering(SNNU).
文摘In this work,dense CdCu_(3)(Al_(l/2)Ta_(l/2))xTi_(4)-xO_(12)ceramics were prepared by a conventional solid phase method.The effect of Al3+/Ta5+dopants on the dielectric properties of CdCu_(3)Ti_(4)O_(12)ceramics was systematically investigated.Upon Al^(3+)/Ta^(5+)co-doping,the dielectric properties of CdCu_(3)(Al_(l/2)Ta_(l/2))_(x)Ti_(4-x)O_(12)were significantly enhanced.Particularly,the CdCu_(3)(Al_(l/2)Ta_(l/2))_(0.05)Ti_(3.95)O_(12)material displays a decent dielectric property,where dielectric constants(εr,~27181),loss tangent(tanð~0.069)at a test frequency of 1 kHz are able to satisfy the application temperature requirement of the Y6R capacitor.Surprisingly,the refined grains resulting from Al^(3+)/Ta^(5+)co-doping lead to heightened resistance at grain boundaries,which is closely associated with enhanced dielectric prop-erties.Meanwhile,the giant dielectric property of the materials can be attributed to the effect of the intemal barrier layer capacitance.The obtained results are expected to provide a new idea for obtaining high dielectric constant and low loss tangent in CdCTO-based materials and promote the practical application of such materials.
基金funded by the National Science,Research,and Innovation Fund(NSRF)and the Fundamental Fund of Khon Kaen Universitypartially supported by the Research of Khon Kaen Universitythe Thailand Graduate Institute of Science and Technology(TGIST)for his Ph.D.scholarship[Grant Number SCA-CO-2558-1033-TH].
文摘Colossal permittivity(CP)materials,particularly co-doped TiO_(2) ceramics,have garnered significant attention for their potential in high-performance ceramic capacitors.However,understanding the origin of CP remains a challenge,with the role of doping ratios between acceptor and donor ions largely underexplored.This study addresses this gap by systematically investigating the effects of Ga^(3+)concentrations on the microstructure and CP of Ga_(y)Nb_(0.025)Ti_(0.975-y)O_(2),prepared via the solid-state reaction method.The sintered ceramics exhibited a dense rutile TiO_(2) phase with increasing grain sizes and oxygen vacancies.Notably,CP values as high as 10^(5) were achieved at Ga^(3+)/Nb^(5+)ratio<1.0.Optimal dielectric properties were observed at Ga^(3+)/Nb^(5+)=1.0,yielding a CP of 6.4×10^(4) and a loss tangent<0.03,surpassing the performance of many existing CP materials.Impedance spectroscopy revealed distinct electrical heterogeneity,with conductive grains and highly resistive grain boundaries with activation energies>1.0 eV.Ceramics with 5%Ga^(3+) doping showed diminished CP due to the absence of semiconducting grains.The findings suggest that CP originates from the internal barrier layer capacitor.This study not only elucidates the crucial role of doping ratios in tailoring CP but also establishes a pathway for developing advanced dielectric materials with superior performance for ceramic capacitors.
基金supported by the National Science Foundation under grant NSF-EFRI RESTOR#1038272.
文摘This paper reports on synthesis of polycrystalline complex perovskite CaCu_(3)Ti_(4)O_(12)(as CCTO)ceramic powders prepared by a sol–gel auto combustion method at different sintering temperatures and sintering times,respectively.The effect of sintering time on the structure,morphology,dielectric and electrical properties of CCTO ceramics is investigated.Tuning the electrical properties via different sintering times is demonstrated for ceramic samples.X-ray diffraction(XRD)studies confirm perovskite-like structure at room temperature.Abnormal grain growth is observed for ceramic samples.Giant dielectric permittivity was realized for CCTO ceramics.High dielectric permittivity was attributed to the internal barrier layer capacitance(IBLC)model associated with the Maxwell–Wagner(MW)polarization mechanism.
