DC-bias and visible light effect on dielectric characteristics of La_0.5Cr_0.5TiO_3+δ

La_0.5Cr_0.5TiO_3+δ ceramic sample was prepared via traditional solid-state reaction route. Frequency and temperature dependence of dielectric permittivity were studied in the range of 10² ~ 10⁶ Hz and of 77 ~ 360 K, respectively. It was observed that extraordinarily high low-frequency dielectric constants appeared at room temperature, and dielectric relaxation peaks shifted to higher temperature with increasing frequency. In the dc-bias studies, it was also found that the dielectric permittivity had obviously dc-bias dependence in low frequency, but independence as the frequency above 14 kHz. Interestingly, the dielectric characteristics of the sample had obvious light dependence at room temperature within the measured frequency range. The results demonstrate that visible light improves the dielectric properties of the ceramic by means of I–V and complex impedance analysis.