Thin MgB2 films were deposited by using pulsed laser deposition and ex situ annealing in a Mg atmosphere. The films exhibited critical temperatures of up to 36K, and were preferentially c-oriented on both Al2O3 (r-cut) and MgO(100) substrates. Synchrotron analysis also gave some indications of in-plane texturing. The films exhibited a very fine grain size (1200Å in the basal plane, 100Å along the c-axis) but the general resistivity behavior and marked extension of the irreversible region confirmed that the grain boundaries were not barriers to supercurrents. Upper critical field measurements, with the magnetic field perpendicular or parallel to the film surface, revealed a field anisotropy ratio of 1.8. The HC2 values were considerably higher, with respect to the bulk ones, when the field lay in the basal plane, and the field-temperature phase diagram for the 2 magnetic field orientations suggested the possibility of strongly enhancing the pinning region by texturing.

Growth of c-Oriented MgB2 Thin Films by Pulsed Laser Deposition - Structural Characterization and Electronic Anisotropy. C.Ferdeghini, V.Ferrando, G.Grassano, W.Ramadan, E.Bellingeri, V.Braccini, D.Marré, P.Manfrinetti, A.Palenzona, F.Borgatti, R.Felici, T.L.Lee: Superconductor Science and Technology, 2001, 14, 952-7