Abstract: The present invention relates to a ferroelectric ceramic material which is a Perovskite solid solution comprising a solid solution represented by the formula:Pb.sub.1-a M.sub.a (Mg.sub.1/3 p0 Nb.sub.2/3).sub.x Ti.sub.y Zr.sub.z O.sub.3containing in the solution at least one oxide selected from the group A noted below and at least one oxide selected from the group B noted below.Group A : La.sub.2 O.sub.3 and Nd.sub.2 O.sub.3 ;Group B : ZnO, SnO.sub.2 and Ta.sub.2 O.sub.5.The proposed ferroelectric ceramic material has a large piezoelectric strain constant d. The present invention is further directed to ferroelectric ceramic which is a Perovskite solid solution comprising a solid solution represented by the formula:Pb.sub.1 -aM.sub.a (Mg.sub.1/3 Nb.sub.2/3).sub.x Ti.sub.y Zr.sub.z O.sub.3wherein M is Ba or Sr, x+y+z is 1, a is from 0 to 0.10, x is from 0.05 to 0.70, y is from 0.25 to 0.50 and z is from 0.05 to 0.

Abstract: The present invention relates to a ferroelectric ceramic material which is a Perovskite solid said solution comprising a solid solution represented by the formulaPb.sub.1-a M.sub.a (Mg.sub.1/3 Nb.sub.2/3).sub.x Ti.sub.y Zr.sub.z O.sub.3containing in the solution at least one oxide selected from the group A noted below and at least one oxide selected from the group B noted below, with the proviso that NiO or Fe.sub.2 O.sub.3 is necessarily contained.Group A: La.sub.2 O.sub.3, Bi.sub.2 O.sub.3 and Nd.sub.2 O.sub.3 ;Group B: NiO, Fe.sub.2 O.sub.3, SnO.sub.2 and Ta.sub.2 O.sub.5.The proposed ferroelectric ceramic material has a large piezoelectric strain constant d. The present invention is further directed to a ferroelectric ceramic which is a Perovskite solid solution comprising a solid solution represented by the formulaPb.sub.1-a M.sub.a (Mg.sub.1/3 Nb.sub.2/3).sub.x Ti.sub.y Zr.sub.z O.sub.3wherein M is Ba or Sr, x+y+z is 1, a is from 0 to 0.10, x is from 0.05 to 0.70, y is from 0.25 to 0.50 and z is from 0.

Abstract: Ferroelectric ceramics represented by xPbTiO.sub.3 -yPbZrO.sub.3 -zPb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 -mSrTiO.sub.3 -nSnO.sub.2 -pZnO-qBi.sub.2 O.sub.3 -rX wherein x,y,z,m,n,p,q and r represent amounts by mole, respectively, with the proviso that x+y+z being 1, Z is at least one oxide selected from the group consisting of Dy.sub.2 O.sub.3, Ta.sub.2 O.sub.5, and Y.sub.2 O.sub.3, and wherein x is from 0.25 to 0.50, y is from 0.05 to 0.70, z is from 0.05 to 0.70, m is from 0 to 0.10, n is from 0 to 0.04, p is from 0 to 0.04, q is from 0 to 0.02 and r is from 0.005 to 0.02. The disclosed ferroelectric ceramics have increased relative dielectric constant and/or electromechanical coupling factor, and are suitable for use as actuators.