ELASTIC PROPERTIES OF LI2B4O7 SINGLE-CRYSTAL BY MEANS OF BRILLOUIN-SCATTERING

Brillouin light scattering has been performed to obtain the complete s et of elastic constants for Li2B4O7 Single crystal. The elastic consta nts measured by this technique at room temperature are as follows : c( 11)(E) = 13.84 x 10(10) N/m(2), c(12)(E) = 0.12 x 10(10) N/m(2), c(13) (E) = 3.23 x 10(10) N/m(2), c(33)(E) = 5.22 x 10(10) N/m(2), c(44)(E) = 5.58 x 10(10) N/m(2) and c(66)(E) = 4.91 x 10(10) N/m(2). The birefr ingent influence on the Brillouin frequency shift has been clearly sho wn in the present spectra. We have also confirmed that the unobserved Brillouin signals at several crystal orientations are associated with the pure transverse acoustic modes.