Study of the relation between composition and physical properties of YBaCuO thin films using RBS, NRA, XRD, XAS and ?{variant}(T)
Por:
Cheang Wong J.C., Ortega C., Rochet F., Siejka J., Trimaille I., Mercandalli L.M., Mayca F., Sacchi M.
Publicada:
1 ene 1993
Resumen:
Superconducting YBaCuO thin films with various oxygen contents were prepared by inverted cylindrical magnetron sputtering of a stoichiometric YBaCuO target on a MgO single crystal heated to about 750°C. The samples were cooled to room temperature either (i) at po2 = 0.25 mbar or (ii) at po2 = 1 atm.As-grown samples were characterized by ?{variant}(T) measurements (Tc, ?Tc). The film composition was determined by Rutherford backscattering spectrometry (RBS) in random and channeling geometries, nuclear reaction analysis (NRA) and X-ray diffraction (XRD). The oxygen content, directly measured by RBS and NRA, were compared to that deduced from the c-axis lattice parameter. While for the (i) samples a difference is observed between RBS and XRD results, the latter being inconsistent with both Tc and the oxygen content, for the (ii) samples, a good agreement is found. The copper oxidation state was controlled by X-ray absorption spectroscopy (XAS) of the CuL2,3 edge operated in the total electron yield mode. The results show that for the as-grown YBaCuO films only the Cu(II) state is present. The effect of long temperature annealings in 18O2 and 16O2 atmospheres (T = 650°C, t = 19 h) was also studied. The results are discussed. © 1993.
Filiaciones:
Cheang Wong J.C.:
Groupe de Physique des Solides de l'Université Paris 7 et de l'Université Paris 6, Tour 23, 2 place Jussieu, 75251 Paris Cedex 05, France
Ortega C.:
Groupe de Physique des Solides de l'Université Paris 7 et de l'Université Paris 6, Tour 23, 2 place Jussieu, 75251 Paris Cedex 05, France
Rochet F.:
Groupe de Physique des Solides de l'Université Paris 7 et de l'Université Paris 6, Tour 23, 2 place Jussieu, 75251 Paris Cedex 05, France
Siejka J.:
Groupe de Physique des Solides de l'Université Paris 7 et de l'Université Paris 6, Tour 23, 2 place Jussieu, 75251 Paris Cedex 05, France
Trimaille I.:
Groupe de Physique des Solides de l'Université Paris 7 et de l'Université Paris 6, Tour 23, 2 place Jussieu, 75251 Paris Cedex 05, France
Mercandalli L.M.:
L.C.R. Thomson-CSF, Domaine de Corbeville, 91401 Orsay, France
Mayca F.:
L.C.R. Thomson-CSF, Domaine de Corbeville, 91401 Orsay, France
Sacchi M.:
Laboratoire pour l'Utilisation du Rayonnement Electromagnétique, Centre Universitaire Paris Sud, 91405 Orsay Cedex, France
|