Anomalous increase in the unipolarity of doped lithium niobate crystals in the temperature range 300–400 K

The lithium niobate single crystals doped with B, Zn, and Gd at a content of 0.002–0.44 wt % have been grown. Their domain structure, static and dynamic piezoelectric properties, dielectric properties, and conductivity are investigated over a wide range of frequencies. The dielectric dispersion associated with the Debye-type relaxation process and considerable anomalies in ɛ′22(T) and conductivity are revealed in the temperature range ∼300–400 K. At these temperatures, the piezoelectric modulus d 33 of the initial polydomain crystals LiNbO3: Gd jumpwise increases up to the values close to those for the undoped single-domain crystal. This increase is accompanied by a substantial change in the etch patterns due to the domain structure of the crystal. The nature of the anomalies observed in LiNbO3 in the above temperature range is discussed.

Перевод пока недоступен