Influence of substrate and precursor film composition on morphology and superconducting transition of T1-2212 thin films characterized by microwaves

An influence of various substrates (MgO, LaAlO3, SrTiO3, YSZ, CeO2/r-sapphi re) and Ba-Ca-Cu precursor chemical composition (212, 223) upon morphology and microwave quality of Tl2Ba2CaCu2O8 (T1-2212) thin films has been studie d. Under the same thalliation conditions, T1-2212 phase has been synthesize d in all films independently of the initial precursor film chemical composi tion (212, 223) with almost the same T-c values. However, the film surface morphology and, thus, the microwave surface impedance, both were found to b e strongly dependent from the type of substrate used as well as from the pr ecursor chemical composition. Films with sharp transition to the supercondu cting state were prepared when 212 precursors were deposited on the MgO and /or LaAlO3 substrates. (C) 2001 Elsevier Science B.V, All rights reserved.