Dielectric permittivity measurements in Pb(Ti,Zr)O-3- Sigma (4)(n=1) (PbB'B
1-alpha"O-alpha(3))(n) solid-solution systems demonstrate that the permitti
vity epsilon (T)(33)/epsilon (o) of the solid solutions correlates with the
molar ratio of the more soft-electric to the less soft-electric component
of PB'B1-alpha"O-alpha(3)(gamma). With increasing gamma, epsilon (T)(33)/ep
silon (o) rises because of at gamma >1 and reduction in the density of the
materials at y >> 1.