EPR study of phase transformations in STHSe:Cr3+ crystals of different deuterium concentration

Anisotropy measurements of the EPR spectrum are performed for STHSe:Cr3 and spin Hamiltonian parameters are determined for the paramagnetic complexes present in the crystal. The coordination of the Cr3+ ion in the crystal lattice is elucidated. The phase transitions α→β and α→γ are investigated by EPR. The shape B(T) from the room temperature to -1300C are established for STHSe, STDSe. The change in the parameter (D) with varying temperature is determined for STHSe. The results suggest that, in STHSe and deuterated crystals the paraelectric-ferroelectric phase transitions are of the first order. (author)