Search

Abstract: We report on the electronic charge transfer in cobalt doped fullerene thin films by means of near-edge x-ray-absorption fine structure (NEXAFS) spectroscopy measurement. Co-doped fullerene films were prepared by co-deposition technique and subjected to energetic ion irradiation (120MeV Au) for possibly alignment or interconnect of randomly distributed metal particles. Polarization dependent NEXAFS spectra revealed the alignment of Co and C atoms along the irradiated ionic path. The structural changes in Co-doped as-deposited and ion irradiated fullerene films were investigated by means of Raman spectroscopy measurements. Downshift of pentagonal pinch mode Ag(2) in Raman spectroscopy indicated the electronic charge transfer from Co atom to fullerene molecules, which is further confirmed by NEXAFS at C K-edge for Co-doped fullerene films. [Copyright &y& Elsevier]

Abstract: Modifications of the C70 molecule (fullerene) under swift heavy ion irradiation are investigated. C70 thin films were irradiated with 120MeV Au ions at fluences from 1×1012 to 3×1013 ions/cm2. The energetic ion impacts lead to the destruction of the C70 molecule. To investigate the stability of C70 fullerene, the damage cross-section and radius of the damaged cylindrical zones are evaluated by fitting the evanescence of C70 vibration modes recorded by Raman spectroscopy. Conductivity measurements together with Raman and optical absorption studies revealed that an irradiation fluence of 3×1013 ions/cm2 results in complete amorphization of the carbon structure of the fullerene molecules. [Copyright &y& Elsevier]

We report the x-ray magnetic circular dichroism (XMCD) studies on Fe doped fullerene thin film and bulk highly oriented pyrolytic graphite. The element-specific hysteresis curves were recorded by measuring the XMCD at the Fe L3 edge as a function of the applied field strength at different temperatures. These investigations suggest that Fe doped fullerene is ferromagnetic at room temperature, while Fe atoms are driven to a nonmagnetic/paramagnetic state with the interaction of graphite matrix. [ABSTRACT FROM AUTHOR]

We report the ordering of carbon nanostructures under energetic ion irradiation at low fluence (<5×1011 ions/cm2). Fullerene thin films and multiwalled carbon nanotube (MWCNT) films were irradiated with 200 MeV Au and 60 MeV Ni ions at different ion fluences, respectively. The changes in the irradiated films have been investigated by means of Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction, and Raman spectroscopy. FTIR and Raman spectroscopy show the improvement of vibration strength in low fluence irradiated fullerene and MWCNT films. X-ray diffraction analysis on low fluence irradiated fullerene films revealed the structural order along the (220) atomic planes. [ABSTRACT FROM AUTHOR]