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
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.
