Photoferroelectric phenomena in ferroelectric oxides and a Rayleigh analysis

The recent renaissances in the field of ferroelectric oxides are owing to various photoinduced phenomena. However, the microscopic correlations among various photoinduced physical characteristics are essential for a detailed understanding of the dynamics associated with these phenomena. In this work, the photoinduced dielectric, pyroelectric, and ferroelectric properties of a lead-free $\mathrm{B}{\mathrm{a}}_{0.875}{(\mathrm{B}{\mathrm{i}}_{0.5}\mathrm{L}{\mathrm{i}}_{0.5})}_{0.125}\mathrm{Ti}{\mathrm{O}}_{3}$ ferroelectric oxide are carried out in out-of-plane and in-plane geometry. The dielectric studies under 405-nm light illumination revealed a significant change in dielectric permittivity along with a decrease in Curie temperature. The observed effects are attributed to the change in internal field distribution inflicted by the photogenerated nonequilibrium charge carriers and trapped charges. The sample exhibits a photoinduced significant change in pyroelectric current and the associated polarization. These effects demonstrate that light could be used as an additional degree of freedom to influence the ferroelectric order parameter. The observed photoinduced dielectric and ferroelectric characteristics give the experimental evidence for the theoretical formalism on the photoinduced ferroelectric phenomena. In addition, the Rayleigh analysis performed on this system highlights the strong correlation between the observed photoferroelectric characteristics with the Rayleigh parameters. These findings could widen the understanding of the photoferroelectric characteristics to extend its applications toward advanced optoelectronic devices.