Baric Changes in the Optical Indicatrix of TGS Crystals
with L-threonine Admixture
1Kardash V., 2Romanyuk G., 2Brezvin
R., 1Kurlyak V., 1Stadnyk V.
1Lviv Ivan Franko National University,
8 Kyrylo and Mefodiy Str., 79005, Lviv, Ukraine
2Institute of Physical Optics, 23 Dragomanov
Str., 79005, Lviv, Ukraine
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The influence of uniaxial mechanical stresses, applied along the principal
crystal-physical axes, on the principal values of birefringence ?ni is
studied for TGS crystals with 5% L-threonine admixture. It is revealed
that ?ni are quite sensitive to the mechanical stresses. The baric coefficients
dTc/dsm
for the phase transition temperature appear to be less than those for the
pure TGS. Temperature dependences and dispersion of the piezooptic coefficients
are calculated. The jump-like changes in all of the piezooptic coefficients
occurring at the Curie temperature in the doped crystals are explained
with the contrib-utions of a secondary electrooptic effect.
Key words: birefringence, uniaxial pressure, phase transitions, piezooptic
coefficients
PACS: 77.84.Jd, 42.81.Gs,78.20.Hp
doi 10.3116/16091833/4/4/173/2003
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