Defect chemistry of Ti-doped antiferroelectric Bi0.85Nd0.15FeO3

Aberration corrected scanning transmission electron microscopy revealed that Bi0.85Nd0.15Fe0.9Ti0.1O3 ceramics contain coherent Nd-rich precipitates distributed throughout the perovskite lattice, implying charge compensation is obtained by the creation of V-Nd''' and not V-Bi'''. At low concentrations, therefore, Ti4+ replace Fe2+ with the creation of 2/3V(Nd)''', and at higher concentrations (when Fe2+ have been eliminated and the conductivity suppressed), Fe3+ with the creation of 1/3V(Nd)'''. The switch in ionic compensation mechanism from 2/3V(Nd)''' at low Ti concentrations (similar to 1%) to 1/3V(Nd)''' at higher concentrations (>1%) results in a decrease in the magnitude of Delta T-C/Delta x, as the disruption of long range anti-polar coupling declines. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705431]