Crystal structure, impedance and broadband dielectric spectra of ordered scheelite-structured Bi(Sc1/3Mo2/3)O4 ceramic

Bi(Sc 1/3 Mo 2/3 )O 4 ceramics were prepared via solid state reaction method. It crystallized with an ordered scheelite-related structure (a = 16.9821(9) Å, b = 11.6097(3) Å, c = 5.3099(3) Å and β = 104.649(2)°) with a space group C12/C1, in which Bi 3+ , Sc 3+ and Mo 6+ are -8, -6 and -4 coordinated, respectively. Bi(Sc 1/3 Mo 2/3 )O 4 ceramics were densifiedat 915 °C, giving a permittivity (ε r ) 24.4, quality factor (Qf, Q = 1/dielectric loss, f = resonant frequency) ~48, 100 GHz and temperature coefficient of resonant frequency (TCF) -68 ppm/°C. Impedance spectroscopy revealed that there was only a bulk response for conductivity with activation energy (E a ) ~0.97 eV, suggesting the compound is electrically and chemically homogeneous. Wide band dielectric spectra were employed to study the dielectric response of Bi(Sc 1/3 Mo 2/3 )O 4 from 20 Hz to 30 THz. ε r was stable from 20 Hz to the GHz region, in which only ionic and electron displacive polarization contributed to the ε r .