Chemical Stability and Crystallographic Analysis of the the Sr₂HoNbO₆ Cubic Perovskite as Potential Substrate for YBa₂Cu₃O_7-δ Superconducting Films

The Sr₂HoNbO₆ complex perovskite has been synthesized by solid-state reaction. X-ray diffraction pattern reveals that Sr₂HoNbO₆ material crystallizes in a cubic structure, Fm3̅m space group, lattice constant a=8.018 Å, which has a lattice mismatch ~3% with YBa₂Cu₃O_7-δ. The chemical stability of Sr₂HoNbO₆ with YBa₂Cu₃O_7-δ superconducting has been studied by x-ray diffraction and measurements of magnetization as a function of temperature on Sr₂HoNbO₆-YBa₂Cu₃O_7-δ composites. X-ray diffraction patterns of the composite shown that all the X-ray diffraction peaks could be indexed for either Sr₂HoNbO₆ or YBa₂Cu₃O_7-δ with no extra peak detectable. This result implies that these compounds remain as two different separate phases in the composite with no chemical interaction. Magnetic response shows that superconducting transition temperature of pure YBa₂Cu₃O_7-δ and Sr₂HoNbO₆-YBa₂Cu₃O_7-δ composites is 93,5 K. These favorable characteristics of Sr₂HoNbO₆ show that it can be used as a potential substrate material for growth of YBa₂Cu₃O_7-δ superconducting films.

Keywords
Complex perovskite; superconducting properties; substrate material; structure