Characterization of anisotropic photoluminescence properties of PMN-0.30PT-Er-Yb ceramics after electric field poling

Abstract

The crystal structure of most ferroelectric materials can be locally distorted by changing the temperature, pressure, or by applying an electric BIAS field. Doping such ferroelectric material with rare-earth (RE) metals activates f-f electronic transitions, resulting in light emission. When external fields are applied to rare-earth-doped ferroelectrics (RE-F), the resulting modification in the local symmetry around the rare-earth dopant sites may promote the tuning of the photoluminescence properties of the RE-F. Such behavior opens great potential for optical applications of RE-F in photonic displays and medical ultrasonic imaging transducers. This work reports the synthesis of Er-Yb-doped PMN-0.30 PT ceramics and the characterization of their physical properties, primarily the photoluminescent ones, aiming to investigate the potential applications of such compounds in piezo-photonics and ferro-photonics devices. The room temperature up-conversion photoluminescence spectrum of the as-sintered ceramic bodies revealed two emissions at about 550 nm and 669 nm corresponding to the transition from ⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 of Er³⁺ ions, respectively. Then, it was verified that the emission intensity is proportional to the nth power of the excitation intensity (${I\propto P}^n$), as proposed by theoretical models. The relationship: ${I\propto P}^n$, were investigated before and after a poling process, and the results were discussed based on the anisotropy in photoluminescent properties driven by changes in the Judd-Ofelt Ω₂ intensity parameter related to the local crystal field around the RE ions in both parallel and perpendicular directions to the applied D.C. electric field.