TY  - JOUR
AU  - Pithan, Christian
AU  - Katsu, Hayato
AU  - Waser, R.
TI  - Heavily donor-doped, optically translucent and ferroelectric barium titanate ceramics through defect chemical engineering
JO  - CrystEngComm
VL  - 21
IS  - 18
SN  - 1466-8033
CY  - London
PB  - RSC
M1  - FZJ-2019-02407
SP  - 2854
PY  - 2019
AB  - The possibility of preparing translucent ferroelectric heavily donor-doped BaTiO3 ceramics rich in TiO2 has been demonstrated by conventional ceramics processing based on the synthesis via the solid state route and on subsequent sintering and annealing at high pressures of oxygen partial pressure. The resulting ceramics possess very high densities and a very fine-grained microstructure with a remarkably narrow grain size distribution. Under oxidizing conditions large amounts of the donor – in this case La – can be incorporated into the perovskite lattice during sintering, as the variation of the lattice parameters determined by combined XRD (X-ray diffraction) and Rietfeld-refinements suggests. The electrons released from these donors are captured most probably by vacancies of titanium, which act as acceptors. The optical properties are largely determined by the defect chemistry and in particular by the concentration of free conducting electrons. Especially the reduction of the free electron concentration is believed to be mainly responsible for the high degree of optical translucency. The normalized values of transmittance almost reach the best values reported so far for nano-crystalline barium titanate powders that have been consolidated via pressure assisted sintering. Measurements of the refractive indices showed that they can be modified by the state of polarization of the ferroelectric BaTiO3-based ceramics. This newly developed material possibly opens a door to novel electro-optical applications.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000467736200014
DO  - DOI:10.1039/C9CE00189A
UR  - https://juser.fz-juelich.de/record/862039
ER  -