Correlation of Tc with the Rare Earth Size in (Ln)Ba2Cu3O6+x Superconductors (Ln = La, Nd, Sm, Eu, Yb “ Cocktails”): Single Crystal X-Ray Diffraction and Electron Microscopy Studies
In a previous paper, structural systematics around non-stoichiometric perovskite derivatives, YBa2Cu3O9−n with n = 1, 2, 3, were developed implying Wadsley’s defects for the non-quantified n values . In this series, YBa2Cu3O6+x (with 0 ≤ x ≤ 1) exhibits remarkable superconductive properties and, in agreement with other reported results, a more precise domain has been found with Tc above 90 K for 0.66 ≤ x ≤ 1. This orthorhombic phase is associated with high Tc values. It is well known that at high temperature, it undergoes an orthorhombic → tetragonal phase transition accompanied by O2 loss, this phenomenon being reversible.
KeywordsRare Earth Tetragonal Phase Bright Field Image Bragg Reflection Orthorhombic Phase
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