Novel titanium dioxide ceramics containing bismuth and antimony

Here,we developed one kind of novel TiO_(2) ceramics with colossal dielectric constant by chemical modifications(Bi^(3+) and Sb^(5+)),and discussed the physical origin for giant dielectric constant.Effects of Bi and/or Sb on their microstructure,dielectric properties as well as its frequency and temperature stability were studied in detail.It was found that their dielectric properties are strongly sensitive to(Bi,Sb)contents,and colossal dielectric permittivity(CP)(10^(4)~10^(5))together with low dielectric loss(~5.7%)can be obtained in a wide composition range.In addition,all the ceramics possessed good frequency(10^(2)~10^(6)Hz)and temperature(-150-200℃)stability of dielectric properties.In addition,the defects caused by the Bi volatilization may be the reason for higher dielectric properties of(Bi_(0.5)Sb_(0.5))_(x)Ti_(1-x)O_(2) ceramics with respect to(A_(0.5)Sb_(0.5))_(x)Ti_(1-x)O_(2)(A=In,Pr,Dy,Sm,Gd,Yb,Ga,Al,Fe or Sc).According to the results of complex impedance and XPS,the electron-pinned defect-dipoles may be suitable to explain the CP phenomenon,and oxygen vacancies-induced by Bi^(3+)&Sb^(5+) substitution for Ti^(4+) should be responsible for conduction mechanism.We believe that this profound investigation can benefit the development of TiO_(2) ceramics as a CP material.