Effects of B-site ions on the electromechanical coupling factors of Pb(B′B")O3-PbTiO3 piezoelectric materials

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 electromechanical 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.