Ba-Cu-Fe-O-Y, Chalcogen, Tetragonal, Y-x polyhedra

• Ba-Ca-Cu-Fe-O-Y
• Ba-Co-Cu-Fe-O-Y
• magnetic properties
• structural properties
• superconductivity
• superconducting transition temperature
• Moessbauer spectra
• disordered
• cuprate
• alkaline
• chalcogen
• high-tc superconductor