Superconducting Transition Temperature in YBa_2Cu_4O_8/La_(2/3)Ca_(1/3)MnO_3/YBa_2Cu_4O_8 Heterostructure

摘要

YBa2Cu4O8/La 2/3Ca 1/3MnO3/YBa2Cu4O8 （Y-124/LCMO/Y-124） heterostructure was prepared by facing-target sputtering technique. The oscillatory superconducting transition temperature was observed when the thickness of LCMO dL is larger than critical thickness dL CR. The metal-insulator transition temperature can only be detected at dL>dL CR. The dependence on the spacer layer in LCMO/Y-124 systems suggests strongly the interplay of ferromagnetic and superconducting couplings.