Impact of Ce Doping on the Relaxor Behavior and Electrical Properties of Sr0.4Ba0.6Nb2O6 Ferroelectric Ceramics

In this work, the rare earth element Ce was incorporated into the A-site of Sr_0.4Ba_0.6Nb₂O₆ ferroelectric ceramics, which was prepared using the conventional solid state reaction method and sintered under different procedures. A comprehensive investigation was conducted to assess the impact of Ce doping and varying sintering procedures on both the relaxor characteristics and electrical properties of the ceramics. When sintered at 1300 °C for 4 h, the grains exhibited an isometric shape. However, when the sintering temperature increases and the holding time prolongs, the grain size increases and presents columnar crystal. The change tendency of dielectric constant is similar with that of the grain size, and the dielectric peak value of samples sintered at 1300 °C for 4 h is the lowest. But the sintering procedure has almost no influence on the Curie point, which notably decreases as the Ce content rises and is primarily governed by the composition. The diffuseness fitting results and the deviation from the Curie-Weiss law indicate that relaxor characteristics increase with the Ce content increasing. The polarization electric (P-E) loops become slimmer with increasing Ce content, verifying the relaxor behavior variation of samples. As a result, the <i>P</i>_max and <i>P</i>_r values decrease and the <i>P</i>_max - <i>P</i>_r value increases with increasing Ce content. Notably, the energy storage density and efficiency enhance obviously with higher Ce content, which is attributed to the relaxor behavior. Furthermore, at a Ce content of 4 mol%, the P-E loops and energy storage performance exhibit remarkable frequency and fatigue stability. Therefore, this study offers valuable insights into the investigation of relaxor behavior and the influence of rare earth elements on the properties of tungsten bronze-structured ferroelectrics.