Microstructure and dielectric properties of (Ca_0.2Sr_0.2Ba_0.2Mg_0.2Bi_0.1Na_0.1)(Ti_1-xZr_x)O₃ high-entropy ceramics

Achieving high dielectric constant with stable dielectric response over wide temperature and frequency ranges remains a major challenge for advanced dielectric ceramics due to the mutual constraint among properties. In this work, high‐entropy perovskite ceramics (Ca_0.2Sr_0.2Ba_0.2Mg_0.2Bi_0.1Na_0.1) (Ti_1−xZr_x)O₃ (HEC6‐ZT) were designed by combining high-entropy with Zr⁴⁺ doping. Structural analysis confirms that all compositions form a single-phase perovskite structure. Increasing Zr⁴⁺ content induced lattice distortion, grain coarsening, and enhanced relaxor behavior, resulting in a non-monotonic evolution of dielectric properties. This evolution is due to the competition between enhanced compositional disorder and reduced intrinsic polarization. Consequently, HEC6-ZT ceramics with x = 0.1 doping showed the optimized dielectric properties, exhibiting high dielectric constant (981 at 1 kHz) and low dielectric loss (0.067), with excellent X7R specification and frequency stability (F_(1M) = 0.15 from 1 kHz to 1 MHz). These results demonstrate the high-entropy and doping strategies provide an effective approach for balancing high dielectric constant and response stability, offering promising candidates for stable dielectric components in advanced electronic devices.