Linear Thermal Expansion of Ferroelectric Deuterated Triglycine Sulphate

Growth, crystal structure, thermal properties and optical anisotropy of Tl4CdI6 single crystals

“…The plates were preliminarily checked for optical homogeneity and residual mechanical strains, using conoscopic patterns observed with a polarising microscope MIN-8. The relative linear thermal expansion L L /  along the c axis as a function of temperature was measured with a computer-controlled quartz dilatometer having a capacitive sensitive element (the thickness sensitivity of 1-2 nm -see, e.g., [22]). The temperature of samples in the region ~ 330-500 K was controlled using a thermostat with the accuracy of about 0.05-0.1 K. Variations of the temperature corresponded to regimes of continuous heating or cooling, with a typical temperature change rate…”

Optical studies of order parameter fluctuations in solid solutions based on lead germanate crystals

“…This correlates well with the known fact that the PT in is more essentially smeared than that in (6). Unlike the method adopted in [16,19] though similar to that used in the studies of critical fluctuations for deuterated triglycine sulphate [20,21], we have put the fitting parameters Table 1.…”

“…Nonetheless, the analysis of fluctuations after the optical activity possesses an evident advantage in this respect, when compare with the analysis based on the optical birefringence or thermal expansion data (see [16,[19][20][21]). Namely, the derivatives of the latter quantities include extra fitting parameters.…”