IMF2017

In the past few years we have discovered a series of unusual phenomena in the super tetragonal compositions of the ferroelectric alloy system (1-x)BiFeO₃-(x)PbTiO₃ (BF-PT) which at x = 0.30 exhibits an anomalously high percentage tetragonality (c/a – 1)x100 ~ 18 %, a value three times of the classical ferroelectric PbTiO₃. The super tetragonal phase of BF-PT exhibits unusual phenomena such as (i) isostructural structural transformation with temperature and (ii) a size driven coupled magneto-ferroelectric criticality at an anomalous size of ~ 300 nm. We have also exploited the practical aspects of the super tetragonal phase. We investigated the photocatalytic properties of BF-PT with regard to dye degradation and discovered that the when the super tetragonal phase was stabilized as metastable phase it enhanced the dye degradation rate five-fold. In another remarkable discovery, we found that by suitable chemical modification of the super tetragonal compositions it is possible to achieve a colossally high electrostrain of 1.3 % - a value comparable to that reported in single crystals of high performance piezoelectric such as PZN-PT.