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The effect of Fe‐acceptor doping on the electrical properties of Na 1/2 Bi 1/2 TiO 3 and 0.94 (Na 1/2 Bi 1/2 )TiO 3 –0.06 BaTiO 3
Author(s) -
Steiner Sebastian,
Seo InTae,
Ren Pengrong,
Li Ming,
Keeble David J.,
Frömling Till
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16401
Subject(s) - dopant , doping , ferroelectricity , acceptor , ionic conductivity , ionic bonding , materials science , solid solution , electrical resistivity and conductivity , conductivity , ceramic , analytical chemistry (journal) , inorganic chemistry , chemistry , dielectric , ion , electrode , condensed matter physics , electrolyte , metallurgy , organic chemistry , physics , optoelectronics , engineering , electrical engineering
Na 1/2 Bi 1/2 TiO 3 (NBT) based ceramics are amongst the most promising lead‐free ferroelectric materials. It was expected that the defect chemistry and the effect of doping of NBT would be similar to that observed for lead based materials, however, acceptor doping does not lead to ferroelectric hardening. Instead, high oxygen ionic conductivity is induced. Nevertheless, for solid solutions with BaTiO 3 (BT), which are more relevant with respect to ferroelectric applications, such a drastic change of electrical properties has not been observed so far. To rationalize the difference in defect chemistry between NBT and its solid solution 94(Na 1/2 Bi 1/2 TiO 3 )–0.06 BaTiO 3 (NBT–6BT) compositions with different concentrations of Fe‐dopant were investigated. The study illustrates that the materials exhibit very similar behavior to NBT, and extraordinarily high oxygen ionic conductivity could also be induced in NBT–6BT. The key difference between NBT–6BT and NBT is the range of the dependence of ionic conductivity with dopant concentration. Previous studies of NBT–6BT have not reached sufficiently high dopant concentrations to observe high conductivity. In consequence, the same defect chemical model can be applied to both NBT and its solid solutions. This will help to rationalize the effect of doping on ferroelectric properties of NBT‐ceramics and defect chemistry related degradation and fatigue.