Critical scattering of synchrotron radiation in lead zirconate–titanate with low titanium concentrations

Diffuse scattering in the lead zirconate–titanate single crystal with a titanium concentration of 0.7 at% has been studied by the synchrotron radiation scattering method. Measurements have been performed both in the vicinity of the Brillouin zone center and at the $M$-point. Highly anisotropic diffuse scattering has been revealed in the paraelectric phase near the Brillouin zone center; diffuse scattering anisotropy is similar to that previously observed in pure lead zirconate. The temperature dependence of this diffuse scattering obeys a critical law with $T_c\approx$ 480 K. Diffuse scattering in the vicinity of the $M$-point weakly depends on temperature; this dependence behaves differently at $M$-points with various indices.