Eur. Phys. J. B 18, 405-411 (2000)
https://doi.org/10.1007/PL00011076

Synthesis and microwave properties of Tl₂Ba₂CaCu₂O₈ superconducting films grown by MOCVD

¹ I.N.F.M and Dipartimento di Scienze Fisiche, Universita' di Napoli Federico II, Napoli, Italy
² Dipartimento di Scienze Chimiche and I.N.S.T.M., Universita' di Catania, Catania, Italy
³ Fachbereich Physik, Bergische Universität Wuppertal, Wuppertal, Germany

Corresponding author: ^a pica@na.infn.it

Received: 16 December 1999
Revised: 17 March 2000
Published online: 15 December 2000

Abstract

We report on the synthesis, structural and electrical characterization of high quality Tl₂Ba₂Ca₁Cu₂O₈ (Tl-2212) superconducting films. The samples have been grown ex-situ on mm² LaAlO₃ (100) substrates by a combined approach of metal-organic chemical vapor deposition (MOCVD) and thallium vapor diffusion. The morphological and compositional nature of the c-axis oriented films has been investigated by SEM and X-ray analyses. Typical values of K and MA/cm² at 77 K have been measured. Microwave measurements have been performed at f = 87 GHz inserting the film in a copper cavity and at f =1.5 GHz on patterned samples using a microstrip resonator technique. A penetration depth nm is evaluated by fitting the microwave data with phenomenological equations. The minimum value of the surface resistance R_s measured at 4.2 K is 60 and 6 m at 1.5 GHz and 87 GHz respectively. The microwave data are described in the context of a modified two fluid model. An evaluation of the temperature dependence of the scattering rate has been performed through the simultaneous measurement of the surface resistance and the penetration depth.