Experimental evidence of electronic polarization in a family of photo-ferroelectrics

Hitesh Borkar, Vaibhav Rao, M. Tomar, Vinay Gupta, James Floyd Scott, Ashok Kumar

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)

Abstract

We report a family of ferroelectric materials which exhibit optical control of dielectric constant, polarization, and conductivity at ambient conditions. The evolution of photo-induced charge carriers under illumination of weak monochromatic light of wavelength λ = 405 nm developed electronic polarization that reorients or enhances the ionic polarization in the direction of the applied electric field, hence significantly increasing the net polarization. The presence of electronic polarization in perovskites, especially ABO3 oxides, and
the contribution to the ionic polarization, is a matter of debate among ferroelectric community; however, recent experimental evidence proved that electronic polarization contributes to overall polarization in different ways: if it is additive, it will act along the direction of ionic polarization; and if it is
subtractive, it will act in the opposite direction. We report a newly developed lead-based ferroelectric family Pb1-x(Li0.5Bi0.5)x(Zr0.2Ti0.8)O3 (PLBZT) for x = 0.3, 0.4, 0.5, which have been successfully synthesized by a conventional solid state reaction route. The X-ray diffraction patterns were recorded at room temperature and refined with Rietveld parameters which confirm its tetragonal structure with P4mm space group symmetry. The Raman spectra, dielectric properties and leakage currents are analyzed. The current conduction mechanisms obey bulk limited Poole–Frenkel model and provide optical dielectric constant similar to theoretical value to lead zirconate titanate.
Original languageEnglish
Pages (from-to)12842-12855
JournalRSC Advances
Volume7
Early online date23 Feb 2017
DOIs
Publication statusE-pub ahead of print - 23 Feb 2017

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