Classification of transition temperature behavior in ferroelectric PbTiO3-Bi(Me′Me)O3 solid solutions -: art. no. 024106

The ferroelectric transition temperature (T-c) behavior of perovskite solid solutions based on PbTiO3-Bi(Me'Me)O-3 (Me'=Fe3+, Zn2+, Sc3+, In3+, Mg2+, Ni2+, etc., and Me=Ti4+, Nb5+, W6+) was considered. Trends in the T-c compositional dependence near the PbTiO3 end member could be described with a geometrical polynomial expression. Three main cases were observed: Case 1, a continued increase in transition temperature above the end member PbTiO3 (495 degrees C); case 2, an increase and then decrease of the transition temperature; and case 3, a continuous decrease in the transition temperature with Bi(Me'Me)O-3 additions. It was noted that for all case 2 examples the enhancement of Delta T-c=T-c(max)-T-c(PT) increased as the distribution of B-site ionic radii increased. A correlation was therefore proposed between the maximum enhancement in transition temperature and the spread of tolerance factor (Delta t) and/or variance in B-site ionic radius (sigma(2)). Finally, it was proposed that these observations are consistent with random-field effects created by local strain-field fluctuations within the perovskite lattice. (c) 2006 American Institute of Physics.