Latest progress on new lead-free antiferroelectric compositions
Material design guided by DFT calculations
19.01.2021 von M. Zhang
In our recent publication entitled (Chem. Mater. 2021, 33, 1, 266–274), Zhang et al. produced a new NaNbO3-based antiferroelectric material that exhibits reversible antiferroelectric to ferroelectric phase transition under the guidance of DFT calculations. “Design of Lead-Free Antiferroelectric (1 – x)NaNbO3–xSrSnO3 Compositions Guided by First-Principles Calculations”
According to their DFT calculations, the ferroelectric order is more energetically stable than the antiferroelectric order by an energy difference of 2.3 meV/f.u. in NaNbO3 while SrSnO3 is predicted to stabilize the antiferroelectric order in NaNbO3 by an energy difference of 1.4 meV/f.u. when 6.25 mol.% of SrSnO3 is incorporated. They processed a series of SrSnO3-modified NaNbO3 ceramic materials using solid-state reactions. It was found that the irreversible antiferroelectric-ferroelectric phase transition in NaNbO3 becomes reversible in SrSnO3-modified new materials. Detailed structural characterizations revealed an increase the unit cell volume and a more disordered, yet less distorted local Na environment, which were related to the stabilization of the antiferroelectric order.