Photo-dielectric effect of Na0.42Bi0.42Ba0.06TiO3−δ lead-free ceramics sintered in nitrogen and oxygen atmospheres

The lead-free ceramics Na[Formula: see text]Bi[Formula: see text]Ba[Formula: see text]TiO[Formula: see text] (BNBT) were prepared via a solid-state sintering method, which was sintered in nitrogen (N 2 ) and oxygen (O 2 ) atmospheres, respectively. The photo-dielectric effect (PDE) of BNBT was studied in detail. The light with a wavelength of 450[Formula: see text]nm and an intensity of 200[Formula: see text]mW/cm 2 was used to illuminate the samples. For both ceramics, the dielectric constant varies periodically with changing light on and off, while dielectric loss is almost unaffected by the light irradiation. The dielectric constant of the ceramics in the studied frequency range between 100[Formula: see text]Hz and 1[Formula: see text]MHz increases under light illumination, demonstrating obvious PDE. The sintering atmospheres and post-annealing atmospheres affect the increased amplitude of the dielectric constant caused by the light irradiation. The results demonstrate that the PDE of the BNBT ceramics can be regulated by using the processing atmospheres, thus providing guidance for regulating the PDE of lead-free ceramics.