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Author (up) Haberkorn, N.; Bengio, S.; Suárez, S.; Pérez, P.D.; Hofer, J.A.; Sirena, M.
Title Effect of thermal annealing and irradiation damage on the superconducting critical temperature of nanocrystalline γ-Mo2N thin films Type Journal Article
Year 2019 Publication Materials Letters Abbreviated Journal
Volume 236 Issue Pages 252-255
Keywords Nitrides; Sputtering; Superconductivity; Irradiation
Abstract We report on the influence of the disorder and stoichiometry in the resulting superconducting critical temperature of γ-Mo2N thin films. Initially, three films (with Tc values of 7.6 K, 6.8 K and 6 K) were grown at room temperature by reactive sputtering, on Si (1 0 0) using different N2/(Ar+N2) mixtures. The influence of the thermal annealing up to 973 K and irradiation damage produced by 1 MeV Zr+(fluence up 2 × 1014 cm−2) is analyzed. The Tc of pristine films remains unchanged for increasing irradiation doses up 2 × 1014 cm−2. The Tc for annealed films decreases close to the value expected for bulk samples (≈5 K) for increasing the annealing temperature. Successive irradiations of the annealed films tend to increase their Tc up to its initial values (before annealing). The results indicate that the Tc in nanometric grain size γ-Mo2N thin films is affected by both nitrogen stoichiometry and disorder at the atomic scale.
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ISSN 0167-577x ISBN Medium
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Call Number BT @ pedrazp @ Serial 850
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Author (up) Haberkorn, N.; Bengio, S.; Suárez, S.; Pérez, P.D.; Sirena, M.; Guimpel, J.
Title Effect of the nitrogen-argon gas mixtures on the superconductivity properties of reactively sputtered molybdenum nitride thin films Type Journal Article
Year 2018 Publication Materials Letters Abbreviated Journal Materials Letters
Volume 215 Issue Pages 15-18
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Notes Cited By :1; Export Date: 14 March 2018 Approved no
Call Number BT @ jguimpel @ Serial 783
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Author (up) Haberkorn, N.; Bengio, S.; Troiani, H.; Suárez, S.; Pérez, P.D.; Granell, P.; Golmar, F.; Sirena, M.; Guimpel, J.
Title Thickness dependence of the superconducting properties of γ- Mo<inf>2</inf>N thin films on Si (001) grown by DC sputtering at room temperature Type Journal Article
Year 2018 Publication Materials Chemistry and Physics Abbreviated Journal Mater. Chem. Phys
Volume 204 Issue Pages 48-57
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Notes Cited By :1; Export Date: 14 March 2018 Approved no
Call Number BT @ jguimpel @ Serial 785
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Author (up) Haberkorn, N.; Suárez, S.; Pérez, P.D.; Troiani, H.; Granell, P.; Golmar, F.; Lee, J.-H.; Moon, S.H.
Title Effect of mixed pinning landscapes produced by 6 MeV oxygen irradiation on the resulting critical current densities Jc in 1.3 µm thick GdBa2Cu3O7-d coated conductors grown by co-evaporation Type Journal Article
Year 2017 Publication Physica C: Superconductivity and its Applications Abbreviated Journal Physica C
Volume 542 Issue Pages 6-11
Keywords Coated conductors; Vortex dynamics; Glassy exponents; Irradiation
Abstract We report the influence of crystalline defects introduced by 6 MeV 16O3+ irradiation on the critical current densities Jc and flux creep rates in 1.3 µm thick GdBa2Cu3O7-δ coated conductor produced by co-evaporation. Pristine films with pinning produced mainly by random nanoparticles with diameter close to 50 nm were irradiated with doses between 2 × 1013 cm−2 and 4 × 1014 cm−2. The irradiations were performed with the ion beam perpendicular to the surface of the samples. The Jc and the flux creep rates were analyzed for two magnetic field configurations: magnetic field applied parallel (H║c) and at 45° (H║45°) to the c-axis. The results show that at temperatures below 40 K the in-field Jc dependences can be significantly improved by irradiation. For doses of 1 × 1014 cm−2 the Jc values at μ0H = 5 T are doubled without affecting significantly the Jc at small fields. Analyzing the flux creep rates as function of the temperature in both magnetic field configurations, it can be observed that the irradiation suppresses the peak associated with double-kink relaxation and increases the flux creep rates at intermediate and high temperatures. Under 0.5 T, the flux relaxation for H‖c and H||45° in pristine films presents characteristic glassy exponents μ = 1.63 and μ = 1.45, respectively. For samples irradiated with 1 × 1014 cm−2, these values drop to μ = 1.45 and μ = 1.24, respectively
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ISSN 0921-4534 ISBN Medium
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Notes Approved no
Call Number BT @ pedrazp @ Serial 771
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Author (up) Hofer, J.A.; Bengio, S.; Rozas, G.; Pérez, P.D.; Sirena, M.; Suárez, S.; Haberkorn, N.
Title Compositional effects on the electrical properties of extremely disordered molybdenum oxynitrides thin films Type Journal Article
Year 2020 Publication Materials Chemistry and Physics Abbreviated Journal Mater. Chem. Phys.
Volume 242 Issue Pages 122075
Keywords Molybdenum; Oxynitrides; Thin films; Sputtering; Electrical transport
Abstract Molybdenum oxynitride (MoNxOy) thin films were grown by reactive sputtering on Si (100) substrates at room temperature. The partial pressure of Ar was fixed at 90%, and the remaining 10% was adjusted with mixtures N2:O2 (varying from pure N2 to pure O2). The electrical properties of the films depend on the chemical composition. Thin films grown using mixtures up to 2% O2 have γ-Mo2N phase and display superconductivity. The superconducting critical temperature Tc reduces from ∼6.8 K to below 3.0 K as the oxygen increases. On the other hand, the films are mostly amorphous for gas mixtures above 2% O2. The electrical conductivity shows a semiconductor-like behavior well described by variable-range hopping conduction. The analysis of the optical properties reveals that the samples do not have a defined semiconductor bandgap, indicating that the high structural disorder produces electron excitation for a wide range of energies.
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Series Volume Series Issue Edition
ISSN 0254-0584 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 860
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