Dielectric Anomalies and High-Temperature Dielectric Relaxation Dependence on B-Site Ordering of Li-Substituted Pb(Yb1/2Nb1/2)O3

B-site ordering of Li-modified Pb0.95Li0.05(Yb1/2Nb1/2)O3 (PLYN) ceramics can be changed by duration during sintering. In this paper, the conventional solid-state reaction method was employed to prepare antiferroelectric perovskite Li-substituted PLYN ceramics. Crystal structure evolution dependence of sintering time was investigated using X-ray diffraction (XRD), Raman spectroscopy, and dielectric response. Two dielectric anomalies responses, attributed to the transition from B-site order to disorder and antiferroelectric-paraelectric phase transition depend on B-site ordering. The high-temperature dielectric relaxation associated with charged carries (oxygen-vacancy hopping) was characterized by isothermal electric modulus and universal dielectric response. Impedance spectroscopy was used to uncover the relationship between defect type and the oxygen partial pressure (pO2) dependence on sintering time in PLYN systems. These findings provide new insights into the interplay among B-site ordered phase structure, dielectric response, and defect types.