Optical study of LiKSO4 crystals under uniaxial pressure.

Abstract

An optical study of ${\mathrm{LiKSO}}_{4}$ crystals under uniaxial pressure is presented. The evolution of the birefringence \ensuremath{\Delta}${\mathit{n}}_{\mathit{a}\mathit{b}}$ and \ensuremath{\Delta}${\mathit{n}}_{\mathit{b}\mathit{c}}$ has been measured in the temperature range 100\char21{}300 K. A ferroelastic monodomain has been induced in the biaxial low-temperature phase by means of uniaxial pressure applied perpendicular to the c axis. The dependence of the birefringence \ensuremath{\Delta}${\mathit{n}}_{\mathit{a}\mathit{b}}$ with respect to the applied uniaxial pressure ${\mathrm{\ensuremath{\sigma}}}_{\mathit{y}\mathit{y}}$ has been measured and related to the piezo-optic coefficients ${\mathrm{\ensuremath{\pi}}}_{\mathit{i}\mathit{j}}$. Our conclusions seem to conciliate the discrepancies presented in previous optical studies of ${\mathrm{LiKSO}}_{4}$ crystals.