Using the high-accuracy principles, spontaneous and induced parametric phenomena are studied in lead germanate-silicate Pb5(Ge1-xSix)3O11 (x equals 0.4) crystals near the ferroelectric phase transition. The symmetry of the phasers is appropriate for simultaneous measuring all the effects. It is essential that at re- polarizing crystals under the electric field, the optical activity sign changes, while the linear birefringence remains unaltered. This enables to find easily the parameters related to the systematic polarimetric errors. Although the crystals mentioned may be regarded as typical ferroelectrics with the second order phase transition, the temperature and the field dependencies of the effects measured depends notably on the sample conductivity, the domain structure and the light scattering at structural defects.
|