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Demonstrates that high pressure chemical vapor deposition (HPCVD) is an effective and efficient approach to the synthesis of thick magnesium boride films over the stainless substrate. X-ray diffraction pattern of magnesium boride film grown on the stainless steel substrate; Deposition rate of the film; Tenacity and the bonding strength of the film to the substrate.

Abstract: Superconducting YBa2Cu3O7− x thin films were deposited on LaAlO3 (100) substrates by a photo-assisted metal-organic chemical vapor deposition (MOCVD) technique. In our experiment, growth temperature, chamber pressure and growth time were all fixed; the only process variable was the susceptor inclination angle (Φ) between the axis of gas inlet and the susceptor surface. It was found that the growth rate of YBCO films increases monotonically as Φ increases, whereas the superconducting critical current density (J c) has a maximum (1.2×106 A/cm2) near Φ =22.5°. The experimental results were found to be well correlated with the three-dimensional simulations of gas flow inside the MOCVD reactor, with Φ being the only process variable. [Copyright &y& Elsevier]

Abstract: We have made a progress in fabricating MgB2 films, ∼25μm, on the stainless steel substrate by hybrid physical–chemical vapor deposition. The superconducting transition temperature is, T C (onset)=39.6K with a transition width, ΔT =0.5K. The characterization by scanning electron microscope and X-ray diffraction indicates that its structure is polycrystalline. At T =0K, the upper critical field H C2 is determined as 15.2T by extrapolation from a polynomial fitting to the transition temperatures under various applied fields, T C(H). In the self field, the critical current density J C is determined as 3.74MA/cm2 at T =15K by a magnetic measurement according to the Bean model. [Copyright &y& Elsevier]

High quality single-crystal magnesium diboride (MgB2) nanowires with lengths exceeding 10 μm were successfully synthesized by hybrid physical chemical vapor deposition. The magnetization and electrical transport properties of single-crystal MgB2 nanowires (NWs) were measured. The superconducting transition temperature of the NWs was 37 K, as confirmed by magnetization measurements. The disordered behavior of the nanowires was observed by four-terminal current–voltage characteristic measurements of an individual NW from T = 10 to 300 K. The temperature-dependent resistivity curves for seven NWs collapsed into a universal curve described by the variable range hopping model, showing intrinsic nonmetallic transport properties. This implies that the granular superconducting defect states are critical to the superconductivity of the individual MgB2 NWs. [ABSTRACT FROM AUTHOR]