The feasibility of using silver on the perovskite A-site in high-performance lead-free piezoelectrics was investigated using density functional theory calculations. A morphotropic phase boundary near (AgNbO 3) 3/8 (PbTiO 3) 5/8 was predicted for the AgNbO 3-PbTiO 3 solid solution. An unusual sequence of compositional phase transitions in AgNbO 3-BaZrO 3 and AgNbO 3-BaTiO 3 was observed which was due to the effects of volume expansion in perovskites. The results of the calculations show that silver atoms are ferroelectrically active and can off-center by 0.5 Å.
Bibliographical noteFunding Information:
This work was supported by the Office of Naval Research, under grant No. N-000014-00-1-0372 and through the Center for Piezoelectrics by Design. The authors also acknowledge the support of the National Science Foundation, through the MRSEC program, Grant No. DMR00-79909. A.M. R. acknowledges the support of the Camille and Henry Dreyfus foundation. Computational support was provided by the Center for Piezoelectrics by Design, the DoD HPCMO, and DURIP. The authors also like to thank Peter K. Davies for stimulating discussion.