Structural transformations in nonstoichiometric YBa 2 Cu 3 O 6 + δ

摘要: Structural-transformation kinetics in YBa{sub 2}Cu{sub 3}O{sub 6+{delta}} caused by oxygen ordering is considered. The effect of long-range interaction between atoms, Coulomb repulsion, and strain-induced on investigated terms crystal-lattice-site diffusion theory. Computer simulations the interacting O atoms give a complicated sequence atomic-scale mesoscale structural transformations. It shown that transformation path strongly influences crystallographic structure ordered phases. An interrelation atomic structures, which proves to be coupled interaction, found. following structures are obtained: primary tweed transforms into (110) polytwin structure, secondary tweed, glassy'' state, as well 2{ital a}{sub 0}{times}2{ital 0} 2 {radical}2 {ital 0}{times}2 superstructures. Two states, mesoscopic phases---metastable (or stable) phases whose phase identity mostly determined their rather than structure. morphologies generated this computer simulation were reported many experimental studies.