Improving photodielectric response properties of (K0.5Na0.5)NbO3 translucent ceramics by Ca(Mg1/3Nb2/3)O3 doping

A series of (1−x)(K0.5Na0.5)NbO3−xCa(Mg1/3Nb2/3)O3 (KNN-xCMN) translucent ceramics were prepared for light-triggering capacitor. The samples illustrate perovskite structure, and its phase transition at room temperature is from the orthorhombic phase to the tetragonal phase. The CMN can inhabit grain growth, resulting in an obvious decrease of grain size. The hysteresis loops gradually transit to the pinched loop. The dielectric peaks evolve from two to one, and the Curie temperature decreases from ~ 400 °C to ~ 100 °C. The transmittance of the KNN-0.1CMN ceramic at 1100 nm is about 66%. The photodielectric response is composition and frequency dependent. A high dielectric tunability at 365 nm can reach up to ~ 900% at 80 Hz and ~ 20% at 100 kHz. An obvious optical switching behavior is achieved. The origin of the photodielectric response is considered to be photo-induced polar domain. Therefore, the designed ceramics have potential application in the contactless light-induced devices.