The polymorph phase stability ranges have been studied for the Bi4V2-xMexO11-y solid solutions with Me = Ga and Zr at room temperature. The formation of orthorhombic α- (x = 0.0 and 0.05) and β-phases (x = 0.1, 0.15) and tetragonal phase (0.2 ≤ x ≤ 0.3) has been revealed in BIGAVOX solid solutions. In BIZRVOX solid solutions, α-phase exists at x ≤ 0.05, while β-phase exists at 0.1 ≤ x ≤ 0.3. The second order phase transitions at ~ 308°C (BIGAVOX) and ~ 270°C (BIZRVOX) have been revealed for solid solutions with x = 0.05 using the SHG and DSC methods. In both systems, the β↔γ-phase transition temperatures have been found to decrease with increasing x.

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Ceramic solid solutions Bi 4 (V 1−x Me x ) 2 O 11−y with x = 0 ÷ 0.3, Me = Zr, Ga, Fe were prepared by the solid state reactions and were studied by the DTA/DSC, X-ray diffraction, dielectric spectroscopy and the second harmonic generation (SGH) method. The temperature dependences of the SHG signal confirmed the noncentosymmetric structure of the samples with x ≤ 0.05 at room temperature. Similar features were observed in the SHG and dielectric property measurements, which give an indication of the strong domain walls "pinning" by oxygen vacancies inherent to the Bi 4 (V 1−x Me x ) 2 O 11−y structures.

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