OPTICAL STUDY OF LIKSO4 CRYSTALS UNDER UNIAXIAL PRESSURE

An optical study of LiKSO4 crystals under uniaxial pressure is present ed. The evolution of the birefringence DELTAn(ab) and DELTAn(bc) has b een measured in the temperature range 100-300 K. A ferroelastic monodo main 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 DELTAn(ab) with respect to the applied uniaxial pressure sigma(yy) has been measured and related to the piezo-optic co efficients pi(ij). Our conclusions seem to conciliate the discrepancie s presented in previous optical studies of LiKSO4 crystals.