ELECTRO-MECHANICAL PROPERTIES OF (PB,LN) (TI,MN) O3 CERAMICS (LN=RARE EARTHS)

Electromechanical properties of PbTiO//3 ceramics modified by the partial substitution of rare earths for Pb, particularly, (Pb, Ln) (Ti, Mn)O//3 (Ln equals La, Pr, Nd, Sm, or Gd) ceramics, are examined. It is found that the Sm substitution for Pb dramatically increases the ratio of electromechanical coupling factor of the thickness dilatational mode to that of the planar extensional mode. Extensive studies of the resonant properties of rectangular strip resonators make it clear that the Sm-substituted PbTiO//3 ceramics are very useful for high-frequency array transducer applications. It is also shown that the pulse responses of array transducers can be improved using Sm substituted PbTiO//3 ceramics instead of other PbTiO//3 ceramics studied here.