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Orientational dynamics in the isotropic phase of a comb-shaped nematic polymer with mesogenic and functional side groups was studied using the Kerr effect and dielectric spectroscopy. For the first time, it was found that in a mesogenic polymer, in contrast to lowmolecular-weight mesogens, the relaxation of the electric birefringence of a melt above the temperature of the nematic-isotropic phase transition can be presented by a sum of several exponential processes, two of which play a decisive role. These main processes replace each other in a temperature range of about 50 degrees. Dielectric spectroscopy also made it possible to distinguish two processes of orientational relaxation: the first is due to rotation of the side mesogenic groups, and the second is associated with motion of the main chain segments.The isotropic phase of liquid crystals (LC) is characterized by a short-range order build-up as it approaches the temperature of phase transition (Т с ) to LC state. The short-range order plays a significant role in a number of physical phenomena observed in the isotropic phase of LC, including static electric birefringence (EB or the Kerr effect) and EB relaxation in a pulsed electric field [1][2][3][4][5][6]. The discussed effects are typical for the temperature range of several tens of degrees higher than Т с , except for the region that is immediately close to phase transition, where order fluctuations become very big. These effects have been well studied, and the Landau -De Gennes theoretical model [7,8] describing phase transitions in LCs has been successfully used in the analysis of pretransition phenomena in the isotropic phase of low molecular weight LC. According to the theory, EB relaxation time τ in an isotropic melt of LC depends on temperature as τ ∝ ν/(T-T*) γ . Here, ν is the viscosity coefficient, Т* is the temperature of the imaginary second-order phase transition, which is about 1 degree higher than Т с . In theory, the exponent γ is equal to 1 that is confirmed by the experiment for low

We report the caloric and magnetocaloric properties of the DyxY3−xAl5O12 garnet single crystals (x = 0, 0.15, 0.5, 1, 1.5, 2.25, 3) studied within a large temperature range at magnetic fields up to 70 kOe. Heat capacity at zero field revealed that the Schottky anomalies ascribed to magnetic splitting the ground Kramers doublet of Dy3+ ions induced by neighbor ions. The low-temperature heat capacity was fitted by a sum of the Debye and Schottky contributions. The antiferromagnetic transition above 1.9 K was observed only for the pure dysprosium aluminum garnet. The shifts of the Schottky anomalies in magnetic fields agreed with strong anisotropy of the g-factor of Dy3+ ions in the c-sites. The Dy3+ ions in the non-stoichiometric positions caused additional weak anomalies in the heat capacity. The heat capacity for the garnet with x = 1 demonstrated strong clustering for this particular composition. The results obtained showed that the measurements of the heat capacity in magnetic field can be used to get information on substitutional disorder and non-stoichiometry in solid solutions. The magnetic entropy was evaluated for the dysprosium-comprising garnets. The pronounced magnitude of the magnetic entropy owing to the Schottky anomalies shows the applicability of the mixed dysprosium yttrium garnets to adiabatic refrigerators.