Influence of A-site Mg2+ incorporation on the structural, optical, dielectric, and ferroelectric properties of BaZr0.1Ti0.9O3 perovskite ceramics

Abstract

Lead-free ferroelectric ceramics have emerged as critical alternatives to toxic lead-based systems for next-generation dielectric and energy storage applications. In this work, Ba1−yMgyZr0.1Ti0.9O3 (y = 0.00, 0.05, 0.07, 0.10) ceramics were synthesized via citrate–nitrate auto-combustion and systematically investigated to understand the influence of A-site Mg2+ substitution on structural, optical, dielectric, ferroelectric, and energy-storage properties. Rietveld refinement confirmed phase-pure tetragonal symmetry (P4mm) across all compositions, with progressive lattice contraction from 4.0266 to 3.9909 Å, while average crystallite size decreased from 21.71 nm (BZT) to 17.21 nm (BMZT0.10) as Mg content increased. HR-SEM revealed a monotonically decreasing grain size from 116.87 to 112.76 nm, confirming Mg2+ as an effective grain growth inhibitor. A tunable optical bandgap of 3.23–3.31 eV was established from UV–Vis diffuse reflectance spectra. Frequency-dependent dielectric measurements revealed Maxwell–Wagner-dominated polarization behavior, with BMZT0.05 achieving the highest permittivity (5069.49) and lowest loss factor (0.019). P–E hysteresis analysis confirmed ferroelectric loops across 5–55 kV/cm at 10 and 100 Hz, with BMZT0.05 exhibiting the highest remanent polarization. Notably, BMZT0.10 achieved an energy-storage efficiency of 85.6% at an ultralow field of 5 kV/cm, attributed to its slim hysteresis loop and enhanced polarization reversibility. These results establish Mg-engineered BZT ceramics as promising lead-free candidates for low-voltage dielectric capacitors, ferroelectric memory, and microelectronic energy-storage applications.