Research on lattice cooperative relaxation modulated by orbital hybridization regulation in NBT–SBT-based ceramics

Abstract

NBT–SBT ceramics are widely utilized in integrated circuits due to their excellent relaxor properties. In this work, a modified NBT–SBT-based ceramic with excellent dielectric properties was prepared via orbital hybridization engineering that can achieve lattice-dominated synergistic relaxation. Driven by the high-entropy effect induced by multiple ions, the crystal adopts a single Pm-3m cubic structure, which promotes the redistribution of orbital hybridization. A high εr is attained via strong orbital coupling between Sr-d, Ti-d, Ta-d, and O-2p orbitals, while a low tan δ is realized through weakly coupled ionic bonding among Na, Mg, and O. Furthermore, donor doping with high-valent Ta5+ and acceptor doping with low-valent Mg2+ reduce the concentration of oxygen vacancies and optimize the chemical environment of Bi3+, which in turn shifts the Tm and TB to higher temperatures and ultimately yields a relaxation mechanism dominated by lattice-mediated cooperative interactions.