Effects of B-site Ions on the Electromechanical Coupling Factors of Pb(B^′B^′′)O₃–PbTiO₃ Piezoelectric Materials

Abstract

The effect of B-site ions of Pb(B ′ B ′′ )O 3 –PbTiO 3 (B ′ =Zn, Mg, Ni, Ga, Sc, In, Yb and B ′′ =Nb, Ta) piezoelectric materials on the electromechanical coupling factors has been studied. A relationship between electromechanical coupling factor k p near a morphotropic phase boundary (MPB) and an order/disorder tendency of B-site ions is systematically discussed. The reason why k p of Pb[((Sc 1/2 Nb 1/2 ) 0.58 Ti 0.42 )O 3 (PSNT59/42) is larger than that of Pb[(Mg 1/3 Nb 2/3 ) 0.68 Ti 0.32 ]O 3 (PMNT68/32) or Pb[((Sc 1/2 Ta 1/2 ) 0.58 Ti 0.42 )O 3 (PSTT55/45) was explained in terms of the disorder tendency of B-site ions of Pb(B ′ B ′′ )O 3 –PbTiO 3 . It may be concluded that a combination of the B-site elements which have a tendency of disorder play an important role in bringing about large electromechnical coupling factors in MPB composition. From this viewpoint, MPB compositions of Pb[((Sc 1/2 Nb 1/2 ) 0.29 (Mg 1/3 Nb 2/3 ) 0.34 Ti 0.37 ]O 3 (PSMNT 29/34/37) and Pb[((Sc 1/2 Nb 1/2 ) 0.36 (Ni 1/3 Nb 2/3 ) 0.26 Ti 0.38 ]O 3 (PSNNT 36/26/38) maybe the two best combinations among all the Pb((B ′ B ′′ )O 3 –PbTiO 3 systems.