Effect of Mg and Mn co-doping on the high electrical properties of BiFe1-2xMgxMnxO3-BaTiO3 lead-free ceramics prepared by sol-gel method and two-step sintering method

Lead-free 0.7BiFe1-2xMgxMnxO3-0.3BaTiO3 (BFMMxO-BTO) piezoceramics were prepared through the sol-gel method followed by a two-step sintering process and the crystal structure and the surface morphology, dielectric, polarization, and piezoelectric properties of lead-free BFMMxO-BTO ceramics were investigated. Through the synergistic effects ofMn and Mg ions to reduce the oxygen vacancies and prevent the formation of defect complexes, the electric performance of lead-free BFMMxO-BTO ceramics was improved. A large remnant polarization (2Pr= 93.8 mu C/cm2), low leakage current (4.93 x 10-7 A/cm2), excellent piezoelectric constant (d33= 193 pC/N), high unipolar strain (0.202%), and high piezoelectric actuator constant (d similar to 33 = 284 pm/V) were obtained for BFMMxO-BTO ceramics with x= 0.04. These results not only demonstrate that (Mg, Mn)-doped BFO-BTO ceramics are a promising, stable, and reliable candidate material with properties for sustainable piezoelectric applications, and shed light on the necessity of developing high-performance piezoelectric materials.