Synthesis and properties of β type Bi(III)2?2xDy(II)2xO3 ? xx solid solution

In the present work, tetragonal β type Bi(III)_{2 − 2x}Dy(II)_2xO_{3 − x}■_x (■:,empty oxygen site) solid solutions have been synthesized in the ranges 0.06 ≤ x ≤ 0.08 at 750°C and 0.05 ≤ x ≤ 0.09 at 800°C by doping small amounts of Dy₂O₃ into monoclinic α -Bi₂O₃. X-ray powder diffraction (XRD) has been used for characterisation of the doped Dy₂O₃ powders as well as for calculation of the unit cell parameters. The polymorphic phase transitions, crystallographic properties, particle sizes, the scanning electron microscope (SEM) microprobe analysis and Dy₂O₃ content dependence of the lattice parameters of the observed β-phase has been reported. The obtained solid solutions had nonstoichiometric character and nonstoichiometry increases with the increasing amount of Dy₂O₃ addition. The experimental results suggested that oxygen vacancies are present in the crystal structure of Dy₂O₃ doped β type solid solutions.