It is shown that Raman scattering from polycrystalline piezoelectric solids contains all of the essential features of Raman single-crystal spectra even when the crystal spectrum is quite anisotropic. As an illustration of the Raman powder technique, the ceramic ferroelectric-antiferroelectric system PbTi${\mathrm{O}}_3$-PbZr${\mathrm{O}}_3$ has been investigated and the "soft" $E\left(\mathrm{TO}\right)$ optical phonon modes measured in the tetragonal ferroelectric region.

• Received 24 August 1970

DOI:https://doi.org/10.1103/PhysRevLett.25.1191