Oxygen-vacancy-related low-frequency dielectric relaxation and electrical conduction inBi:SrTiO

Abstract

The temperature dependence of dielectric properties and electrical conduction of (Sr 1Ϫ1.5x Bi x )TiO 3 (0.0133рxр0.133) was measured from 10 to 800 K. Three sets of oxygen vacancies related dielectric peaks ͑peaks A, B, and C) were observed. These peaks could be greatly suppressed or eliminated by annealing the samples in an oxidizing atmosphere, and enhanced or recreated by annealing in a reducing atmosphere. The results show that the Maxwell-Wagner polarization is not the main mechanism, and the Skanavi's model also cannot be directly applied. A tentative explanation was suggested. Peak A, observed in the temperature range of 100-350 K with the activation energy for dielectric relaxation E relaxA ϭ0.32-0.49 eV, is attributed to the coupling effect of the conduction electrons with the motion of the off-centered Bi and Ti ions; the conduction carriers in this temperature range are from the first ionization of oxygen vacancies (V o ). Peaks B and C are also discussed.

Dielectric response of PLZT ceramics x/57/43 across ferroelectric–paraelectric phase transition

“…The low frequency dielectric dispersion has also been reported for other perovskites (Bidault et al 1994;Ang et al 2000). They also reported that the activation energies for dielectric relaxation and conduction are comparable and represents the same physical nature.…”

“…They further assumed that (a) dipolar relaxation is due to the oxygen vacancies adjacent to Ti 4+ , which may relax between six equivalent sites of unit cell, (b) the mobility of oxygen vacancy is extended to whole sample leading to the ionic conductivity, and (c) storage of free charge carriers at the two material-electrode interfaces, which leads to space charge effect. In fact, such a low frequency dielectric relaxation is very common in Tibased ABO 3 perovskites (Ang et al 2000). The phenomenon of relaxation and conduction in Bi-doped strontium titanate has also been attributed to the ionization of oxygen vacancies (Ang et al 2000).…”

“…In fact, such a low frequency dielectric relaxation is very common in Tibased ABO 3 perovskites (Ang et al 2000). The phenomenon of relaxation and conduction in Bi-doped strontium titanate has also been attributed to the ionization of oxygen vacancies (Ang et al 2000). According to Skanavi model (Bidault et al 1994 and references therein), small motion of Ti 4+ ion can cause the reorientation of dipoles.…”

Frequency and temperature dependent transport properties of NiCuZn ceramic oxide

“…It indicates that the peak belongs to relaxation type peaks. There is a wide consensus that the anomaly appearing in the high temperature range in oxide materials is related to oxygen vacancies [25]. This suggests that the high-temperature anomaly in our sample may be related to oxygen vacancies.…”

Dielectric relaxation in combustion synthesized perovskite SmAlO3

“…Further, defects or non-stochiomertry in perovskite may lead to a mixed ionic and electronic conductivity 10 . These phenomenons were also discussed within the Maxwell-Wagner model in connection with the non-homogeneous structure of compounds 7,[11][12][13] . Oxygen vacancies, resulting from technological processing, influences the electrical properties of the perovskite materials and the oxygen vacancies play an important role in relaxation and transport phenomena 14 .…”