Ultrahigh ferroelectric response in Fe modified 0.95(Na1/2Bi1/2)TiO3-0.05BaTiO3 single crystals

Abstract

Single crystals of x at% Fe + 0.95(Na_1/2Bi_1/2)TiO₃-0.05BaTiO₃ (x%-Fe:NBBT5, x = 0.1, 0.2 and 0.5) with ultrahigh ferroelectric response were developed by introducing defect associations. The very large field-induced bipolar and unipolar strains, i.e., S_max ∼ 1.1%, ε_max/E_max ∼ 1300 pm V⁻¹, d₃₃ ∼ 600 pC N⁻¹ and permittivity tunability ∼120%, demonstrate that these crystals are promising candidates as lead-free ferroelectrics. The presence of ferromagnetic properties further provides their new application potential as multiferroic materials. The defect chemistry and domain structure were studied systematically. The effects of microscopic defect functional centers on macroscopic properties were discussed in detail.