67Zn Mössbauer investigation of lattice-dynamical effects and hyperfine interactions in ZnF2.

Abstract

The temperature dependence of lattice-dynamical effects and of hyperfine interactions in $^{67}\mathrm{ZnF}_{2}$ has been investigated between 4.2 and 55.3 K with use of the 93.3-keV M\ossbauer resonance in $^{67}\mathrm{Zn}$. Within this temperature range the Lamb-M\ossbauer factor decreases from 1.23% to 0.46%. The electric quadrupole tensor characterized by ${\mathrm{eV}}_{\mathrm{zz}}$Q/h=+8.2\ifmmode\pm\else\textpm\fi{}0.1 MHz and \ensuremath{\eta}=0.15\ifmmode\pm\else\textpm\fi{}0.02 is independent of temperature. The data on the quadrupole tensor and on the Lamb-M\ossbauer factor exclude a beginning ferroelectric transition, which was proposed to occur at low temperatures. The results on the isomer shift (relative to ZnO) and on the electric quadrupole tensor are in very good agreement with recent theoretical cluster calculations.