Low-temperature thermal properties and features of the phonon spectrum of lutetium tetraboride

As a result of the approximation of Γ⊥(T), Γ ‖(T) temperature dependencies in accordance with the chosen phonon spectrum model have been found: the anomalies of Γ⊥(T), Γ‖(T) are at about 25 K and then drop at lower temperatures due to the Einstein vibrations of boron sublattices.