Abstract
A Brillouin Scattering system has been built up using a He-Ne laser, piezoelectrically scanned Fabry-Perot interferometer and multiscaler counting system. The angular dependences of frequency shift and intensity of the quasi-longitudinal and quasi-transverse acoustic modes propagated within the plane perpendicular to the ferroelectric b¯-axis for triglycine fluoberyllate have been studied. The quasi-longitudinal components were well resolved within the limits of the 128 multichannel analyzer employed, but the quasi-transverse ones were poorly resolved due to the strong central component caused by imperfections in our single crystal samples. From these results, information about some of the sound velocities, Pockel's coefficients and other physical parameters was obtained and compared to data from triglycine sulfate. An attempt to study the sound velocity relaxation of the quasi-longitudinal modes as a function of temperature through the transition (Tc = 73.3°C) was unsuccessful, but indicated an upper limit of 1% change, similar to the case of triglycine sulfate.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
