STRUCTURAL TRANSITIONS IN 90K SUPERCONDUCTING PEROVSKITE Ba₂LaCu₃0_7-y:A TEM STUDY

An orthorhombic-to-tetragonal structural transition of high Tc Ba₂LaCu₃0_7-y samples was observed with transmission electron microscope( TEM). Two intermediate orthorhombic structures were discovered and discussed. Thus, the Ba₂LaCu₃0_7-y is another member of high Tc Ba₂LnCu₃0_7-y (Ln=Lathanides) family with lower structural transition temperature.