Dependence the microstructure specifications of earth metal lanthanum La substituted Bi<sub>2</sub>Ba<sub>2</sub>CaCu<sub>2-X</sub>La<sub>X</sub>O<sub>8+δ</sub> on cation vacancies

The paper delivers an analyzing and discussion of the experimental results for the effect of lanthanum substitution on the structural behavior for compounds (Bi₂Ba₂CaCu_2-XLa_XO_8+δ) with variation concentrations from 0 up to 0.2 with a fraction of 0.05. Specimens prepared by solid-state reaction. We investigate the structural properties, studying the lanthanum substitution instead of lead using the resulting properties of XRD. The sintering process was done below the melting point of any one of the component materials. The optimum sintering temperature was equal to 850 ℃ for 72 h to produce an active powder with higher densities and reduced the distance between the grains. (FWHM) results were calculated using X-ray information. The crystallite size D was estimated by Scherer and Williamson-Hall equations, where the results showed that the crystallite size (57.029-63.281 nm) and (56.395-65.948 nm) respectively, besides, the degree of crystallinity (41.64-63.79%) correlation with concentrations of lanthanum substitution. Through the outcome values, the results of the three methods are observed close to each other and this indicates that these methods are compatible with the compound and that the partial replacement occurs a noticeable change in the size of the crystallite as well as in the degree of crystallinity.