Giant enhancement in ferroelectric polarization under illumination

AK acknowledges the CSIR-MIST (PSC-0111) project for their financial assistance. Hitesh Borkar would like to acknowledge the UGC (SRF) to provide fellowship to carry out Ph.D program.We report optical enhancement in polarization and dielectric constant near room temperature in Pb0.6Li0.2Bi0.2Zr0.2Ti0.8O3 (PLBZT) electro-ceramics; these are doubly substituted members of the most important commercial ferroelectric PbZr0.2Ti0.8O3 (PZT:20/80). Partial (40%) substitution of equal amounts of Li+1 and Bi+3 in PZT: 20/80 retains the PZT tetragonal structure with space group P4 mm. Under illumination of white light and weak 405 nm near-ultraviolet laser light (30 mW), an unexpectedly large (200-300%) change in polarization and displacement current was observed. Light also changes the dc conduction current density by one to two orders of magnitude with a large switchable open circuit voltage (Vocv ∼ 2 V) and short circuit current (Jscc∼ 5 × 10−8 A). The samples show a photo-current ON/OFF ratio of order 6:1 under illumination of weak light.PostprintPeer reviewe