Navegação Ciências Exatas e da Terra por Assunto "Efeitos de feixe iônico"

Resultados 1-15 de 15

    • Agglomeration defects on irradiated carbon nanotubes 

      Moura, Cassio Stein; Balzaretti, Naira Maria; Amaral, Livio; Lacerda, Rodrigo Gribel; Pimenta, Marcos A. (2012) [Artigo de periódico]
      Aligned carbon nanotubes (CNT) were irradiated in the longitudinal and perpendicular directions, with low energy carbon and helium ions in order to observe the formation of defects in the atomic structure. Analysis through ...

    • Carbon deposition in Si as a consequence of H and He irradiations : a systematic study 

      Mörschbächer, Marcio José; Behar, Moni (2002) [Artigo de periódico]
      In the present work we have investigated the influence of different parameters that determine the C deposition on a Si target. Among them we have studied the pressure of the irradiation chamber, the implantation fluence, ...

    • Competing influence of damage buildup and lattice vibrations on ion range profiles in Si 

      Posselt, Matthias; Mäder, M.; Grötzschel, Rainer; Behar, Moni (2003) [Artigo de periódico]
      Phosphorus depth profiles in Si obtained by 140 keV implantation in the [001] axial channel direction and in a direction 7° off axis are investigated at two different doses (531013 and 5 31015 cm22) for implantation ...

    • Comprehensive study of the effect of the irradiation temperature on the behavior of cubic zirconia 

      Debelle, Aurélien; Channagiri, Jayanth; Thomé, Lionel; Decamps, Brigitte; Boulle, Alexandre; Moll, Sandra; Garrido, Frédérico; Behar, Moni; Jagielski, Jacek (2014) [Artigo de periódico]
      Cubic zirconia single-crystals (yttria-stabilized zirconia (YSZ)) have been irradiated with 4MeV Au²+ ions in a broad fluence range (namely from 5 1012 to 2 1016 cm-²) and at five temperatures: 80, 300, 573, 773, and 1073 ...

    • Confinement effects of ion tracks in ultrathin polymer films 

      Papaleo, Ricardo Meurer; Thomaz, R.S.; Gutierres, L.I.; Menezes, Vivian Machado de; Severin, D.; Trautmann, C.; Tramontina, Diego; Bringa, Eduardo Marcial; Grande, Pedro Luis (2015) [Artigo de periódico]
      We show direct experimental evidence that radiation effects produced by single MeV heavy ions on a polymer surface are weakened when the length of the ion track in the material is confined into layers of a few tens of ...

    • Cratering and plastic deformation in polystyrene induced by MeV heavy ions : dependence on the molecular weight 

      Farenzena, Lucio Sartori; Livi, Rogerio Pohlmann; Araujo, Marco Aurelio de; García Bermúdez, Gerardo Jose; Papaleo, Ricardo Meurer (2001) [Artigo de periódico]
      Cratering and plastic deformation induced by individual MeV ions on the surface of polystyrene thin films of different molecular weights (Mw) (from 3250 to 2 X 10⁷u) are investigated using scanning force microscopy. 20 ...

    • Electrical isolation of GaN by MeV ion irradiation 

      Boudinov, Henri Ivanov; Kucheyev, Sergei O.; Williams, J.S.; Jagadish, Chenupati; Li, Gang (2001) [Artigo de periódico]
      The evolution of sheet resistance of n-type GaN epilayers exposed to irradiation with MeV H, Li, C, and O ions is studied in situ. Results show that the threshold dose necessary for complete isolation linearly depends on ...

    • Electrical isolation of InGaP by proton and helium ion irradiation 

      Danilov, Iuri; Souza, Joel Pereira de; Boudinov, Henri Ivanov; Bettini, Jefferson; Carvalho, Mauro Monteiro Garcia de (2002) [Artigo de periódico]
      Formation of electrical isolation in n- and p-type In0.49Ga0.51P epitaxial layers grown on semi-insulating GaAs substrates was investigated using proton or helium ion irradiation. Sheet resistance increases with the ...

    • Exchange bias in a ferromagnet/antiferromagnet system with TCTN 

      Sossmeier, K.D.; Pereira, Luis Gustavo; Schmidt, Joao Edgar; Geshev, Julian Penkov (2011) [Artigo de periódico]
      This paper reports experimental results obtained on an unconventional exchange bias (EB) system where the ferromagnetic layer, Ni0.75Cu0.25, has lower ordering temperature (TC) than that (TN) of the antiferromagnetic one, ...

    • Ion irradiation effects on the exchange bias in IrMn/Co films 

      Schäfer, Deise; Grande, Pedro Luis; Pereira, Luis Gustavo; Geshev, Julian Penkov (2011) [Artigo de periódico]
      The present work reports on the influence of ion irradiation in exchange-coupled bilayers. Magnetron-sputtered IrMn4 /Co films were irradiated with 40 keV He+ ions and the dependence of their magnetic properties was studied ...

    • Nanoscale density fluctuations in swift heavy ion irradiated amorphous SiO2 

      Kluth, Patrick; Pakarinen, O. H.; Djurabekova, F.; Giulian, Raquel; Ridgway, M.C.; Byrne, A. P.; Nordlund, K. (2011) [Artigo de periódico]
      We report on the observation of nanoscale density fluctuations in 2 μm thick amorphous SiO2 layers irradiated with 185 MeV Au ions. At high fluences, in excess of approximately 5 1012 ions=cm², where the surface is completely ...

    • Ralaxation times of nanoscale deformations on the surface of a polymer thin film near and below the glass transition 

      Papaleo, Ricardo Meurer; Leal, Rafael Gustavo Torres; Carreira, Willian Hasenkamp; Barbosa, Luiz Gustavo de Moura da Silva; Bello, Ivo; Bulla, Agostinho Antônio (2006) [Artigo de periódico]
      We report on measurements of relaxation times of nanometer-sized deformations resulting from the impact of individual energetic ions on poly methyl methacrylate surfaces at temperatures close to and below the glass transition ...

    • Spatial separation of vacancy and interstitial defects formed in Si by oxygen-ion irradiation at elevated temperature 

      Danilov, Iuri; Boudinov, Henri Ivanov; Souza, Joel Pereira de; Drozdov, Yu. N. (2005) [Artigo de periódico]
      A study of damage depth distribution in Si by elevated temperature O+-ion implantation was performed using three structures: (i) bulk Si, (ii) Si/SiO2 /bulk Si, and (iii) SiO2 /bulk Si. The samples were implanted at 250°C ...

    • Structural modifications in FexCo1-x/Cu multilayers induced by ion irradiation 

      Graff, Ismael Leandro; Teixeira, Sergio Ribeiro; Amaral, Livio; Alves, Maria do Carmo Martins; Flores, Wladimir Hernandez (2004) [Artigo de periódico]
      The structural evolution of Fe30Co70 /Cu multilayers under ion irradiation is investigated in detail using x-ray techniques. The samples were irradiated with two different ions, 50 keV of He+ and 600 keV of Kr+, at room ...

    • Tracks and voids in amorphous Ge induced by swift heavy-ion irradiation 

      Ridgway, M.C.; Bierschenk, Thomas; Giulian, Raquel; Afra, Boshra; Rodriguez, M. D.; Araújo, Leandro Langie; Byrne, A. P.; Kirby, Nigel; Pakarinen, O. H.; Djurabekova, F.; Nordlund, K.; Schleberger, M.; Osmani, O.; Medvedev, N.; Rethfeld, B.; Kluth, Patrick (2013) [Artigo de periódico]
      Ion tracks formed in amorphous Ge by swift heavy-ion irradiation have been identified with experiment and modeling to yield unambiguous evidence of tracks in an amorphous semiconductor. Their underdense core and overdense ...