Origin of colossal permittivity in (In1/2Nb1/2)TiO2via broadband dielectric spectroscopy.
(In1/2Nb1/2)TiO2 (IN-T) ceramics were prepared via a solid-state reaction route. X-ray diffraction (XRD) and Raman spectroscopy were used for the structural and compositional characterization of the synthesized compounds. The results indicated that the sintered ceramics have a single phase of rutile TiO2. Dielectric spectroscopy (frequency range from 20 Hz to 1 MHz and temperature range from 10 K to 270 K) was performed on these ceramics. The IN-T ceramics showed extremely high permittivities of up to ∼10(3), which can be referred to as colossal permittivity, with relatively low dielectric losses of ∼0.05. Most importantly, detailed impedance data analyses of IN-T demonstrated that electron-pinned defect-dipoles, interfacial polarization and polaron hopping polarization contribute to the colossal permittivity at high temperatures (270 K); however, only the complexes (pinned electron) and polaron hopping polarization are active at low temperatures (below 180 K), which is consistent with UDR analysis.
College of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710062, China. liupeng@snnu.edu.cn.
Xiao-gang
XG
Zhao
Peng
P
Liu
Yue-Chan
YC
Song
An-ping
AP
Zhang
Xiao-ming
XM
Chen
Jian-ping
JP
Zhou