Ba-Ca-Cu oxycarbonate thin films, prepared by pulsed laser deposition: structure, growth mechanism and superconducting properties

Ba-Ca-Cu oxycarbonate superconducting thin films on LaAlO3 (100) substrates were grown by pulsed laser deposition in off axis geometry. X-ray diffract ion, selected area electron diffraction, and high-resolution transmission e lectron microscopy indicated that the films consisted of different phases o f the (CxCu1-x)Ba2Can-1CunO2n+3 compound. The main phase was the n = 4 phas e (CxCu1-x)Ba2Ca3Cu4O11, besides other phases as the n = 1,2,3,5... phases and precipitates of CaO. The films were grown predominantly a-axis oriented and contained, in a small amount, c-axis oriented domains of the n = 4 pha se near the film surface. An onset of superconductivity at 115 K and critic al temperatures up to 78 K were found by AC resistive and inductive measure ments. (C) 1999 Elsevier Science B.V. All rights reserved.