Measurements of the perturbed $\gamma -\gamma$ directional correlation have been made for the first excited state of ${}_{}{}^{44}{}_{}{}^{}\mathrm{Sc}$ in polycrystalline lead titanate at room temperature. A static electric quadrupole perturbation was observed, having an interaction strength $\left|Q{V}_{\mathrm{zz}}\right|=(3.92\mathrm{}\pm 0.05)\times {10}^{-8\mathrm{}}$ V. Using a recently reported value for the quadrupole moment of the ${}_{}{}^{44}{}_{}{}^{}\mathrm{Sc}$ first excited state, the electric field gradient at the Sc-ion site is found to be $V_{\mathrm{zz}}=(2.2\mathrm{}\pm 0.4)\times {10}^{21}$ V/${\mathrm{m}}^2$. The time-differential attenuation coefficient shows possible effects of a normal probability distribution for the field gradient with a relative width $\delta =0.02\mathrm{}$. No evidence of rhombic fields was found. A comparison of these results with earlier studies of ${}_{}{}^{44}{}_{}{}^{}\mathrm{Sc}$ in BaTi${\mathrm{O}}_3$ shows the electric field gradient at the Sc-ion site in PbTi${\mathrm{O}}_3$ to be larger than in BaTi${\mathrm{O}}_3$ by a factor of 1.46 ± 0.07.

• Received 2 November 1970

DOI:https://doi.org/10.1103/PhysRevB.4.147