Use of the time constant related parameter f_max to calculate the activation energy of bulk conduction in ferroelectrics

Abstract

The use of time constant related parameter fmax to obtain the activation energy for bulk electrical conduction (and any discussion of the possible conduction mechanisms) in ferroelectric materials should be used with caution.

High‐temperature dielectric properties and impedance spectroscopy of PbHf1−xSnxO3ceramics

“…With Sn 4+ doping concentration increases, the radius of arc decreases and maybe because the increase of Sn 4+ reduces the height of grain boundary barrier at this temperature, thus leading to the change of impedance [30]. Besides, a small tail appears on the periphery of the arc in low-frequency range of some graphs (such as x = 0, 0.1, 0.2 and 0.25), which may be related to the electrode effect [31]. Following discussion will ignore it, due to the limit of measurement frequency.…”

“…According to the equivalent circuit fitting results and combined Z and M plots, the dielectric response mainly comes from three aspects: grain core, grain shell and grain boundary. Combined with the R and C values, the lowfrequency responses are related to grain boundary (R 3 , C 3 , n 3 ), and the high frequency responses are involved with the grain core (R 1 , C 1 , n 1 ) and grain shell (R 2 , C 2 , n 2 ) [31,33]. The insets in Fig.…”

Mixed ionic–electronic conduction and defect chemistry of (Na0.5Bi0.5TiO3)1−x(BiCoO3)x (0 ≤ x ≤ 0.06) solid solutions

“…This has been conrmed by our previous studies on the electrical properties of NBT-BiAlO 3 (NBT-BA), NBT-BiGaO 3 (NBT-GB) and NBT-BiScO 3 (NBT-BS) solid solutions. 23,24 s b of NB 0.50 T can be signicantly reduced aer incorporation of these Bi-based perovskites. The ability of B-site acceptordopants to trap oxygen vacancies depends on their ionic size.…”

“…(1) Defect mechanisms. For xed-valence M (M 3+ as an example), previous studies have demonstrated that dominant defect mechanisms in NBT-BiMO 3 can be described by: 23,24 Na…”

“…In previous studies, mixed conduction or electronic conduction of NBT-based materials is obtained by suppressing the ionic contribution; therefore Type II and Type III NBT usually present much lower s b than Type I NBT. 10,23,24 If electronic conduction can be induced by the transition metal ions in BiMO 3 , it is possible to obtain Type II or Type III with high s b . Although this can be detrimental to dielectric applications, it may expand the potential applications of NBT-based materials as cathode materials for electrochemical devices such as solid oxide fuel cells (SOFCs), where high mixed conductivity is required.…”