Mitigating electric leakage by donor impurity and lattice compatibility in phase-transforming ferroelectric materials

Phase-transforming ferroelectrics are widely utilized in pyroelectric devices. However, elevated temperatures lead to significantly increased electric leakage. Mitigating electric leakage near the transformation temperatures is essential for device functionality and lifetime. In this work, we tune the lattice parameters in fine-grained, donor-doped ferroelectric Eu-BTO-Zrxmaterials and discover that tuning lattice parameters effectively suppresses electric leakage. Through first-principles calculations, we investigate the influence of lattice parameters on donor energy level and discover that the donor energy level shifts significantly in Eu-BTO-Zr5 composition, coinciding with the observed leakage mitigation at tetragonal-to-cubic transformation. We analyze the lattice compatibility of developed materials and reveal that the leakage mitigation appears in materials with lattice parameters equating structural anisotropy and lattice compatibility. Our findings clarify the coupled role of donor states and lattice parameters in leakage mitigation across phase transformation, providing a theoretical framework for designing pyroelectric materials with improved thermal stability and reduced leakage.