Fabrication and characterization of Nd1+xBa2−xCu3O7−y thin films deposited by metal–organic chemical vapor deposition using liquid state sources

Abstract We have fabricated Nd 1+ x Ba 2− x Cu 3 O 7− y (NBCO) superconducting thin films by metal–organic chemical vapor deposition (MOCVD) using non-fluorinated sources. At oxygen partial pressures P O 2 =0.85 Torr and P O 2 =0.65 Torr, the films with the composition deviated from the stoichiometry (Nd:Ba:Cu=1:2:3) have better crystallinity than those with the stoichiometric composition. However, at P O 2 =0.01 Torr, high quality c -axis oriented films with the stoichiometric composition are obtained. This is closely related to the Nd–Ba substitution. The films deposited at P O 2 =0.65 Torr show semiconducting properties by DC four prove method and superconducting properties by SQUID measurement. On the other hand, the films deposited at P O 2 =0.01 Torr show superconductivity by both electric and magnetic measurements. TEM-EDX observation on the films deposited at P O 2 =0.65 Torr revealed that the phase separation according to the Nd–Ba substitution was the cause of the different behaviors of electrical and magnetic properties.