Domorats'kyj K. Physical properties and structural peculiarities of Bi2TeO5 single crystal

The object of researches is the Bi2TeO5 single crystal. The work aim is to establish the connection between its physical properties and structural peculiarities. The crystal was grown by the Chochralski technique. For researches it was used resonance-antiresonance, echo-pulse, Raman spectroscopy, X-ray and other methods. It turned out, that at big atom vibration amplitudes in Вi2ТеО5, as distinct from small amplitude case, property anisotropy. That is caused by non-central character interatomic interaction. The presence in Bi2TeO5 structural disorder, which is connected with a lone-pair electron activity, is followed from data obtained. It is established the existence of the first kind phase transition (PT). Identified peculiarities of this PT are typical for improper ferroelectrics. The electromechanical non-linearity of Вi2ТеО5 is revealed. That makes this crystal perspective for practice.