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Thin films of C60 were irradiated with swift heavy ions of Au (100 MeV), Ni (110 MeV) and O (70 MeV) to study the irradiation effects. Films of C60 with thickness ∼230 nm were deposited on quartz and float glass substrates. The samples irradiated by different fluences of ions were studied using optical absorption spectroscopy, in situ conductivity measurements and Raman spectroscopy. Obtained data indicate that swift ions at low fluences result in multiple molecular units like dimer or polymer. High fluence irradiation result in sub-molecular formations in amorphous semiconducting carbon network, indicating overall damage of the fullerene molecules. These sub-molecular units have been identified as nanocrystalline graphite. Observations with optical absorption spectroscopy of decrease in bandgap with increase in fluence, and with in situ resistivity measurements, are in conformity with understanding of structural changes from Raman spectroscopy. A comparison of changes produced by irradiation of these ions which have different electronic energy loss (Se) values, is presented. [Copyright &y& Elsevier]

Effect of swift heavy ion irradiation on the modifications in structural and superconducting properties of La-based mixed oxide thin film superconductors with stoichiometric composition La2−xDyxCayBa2Cu4+yOz (y=2x; x=0.3 and 0.5) have been investigated using 200 MeV Ag+15 ion irradiation. Superconducting thin films of x=0.3 and 0.5 samples synthesized using pulsed laser deposition technique on LaAlO3 substrate were irradiated with 200 MeV Ag ions. Elastic recoil detection analysis (ERDA) studies were performed on the thin films using 15 UD Pelletron facility at NSC, New Delhi, for the determination of the changes in oxygen content. Recoiled Ca, Cu and O atoms were detected using a large-area position sensitive ΔE–E detector telescope to understand the stoichiometric changes with the increase in irradiation dose. From the analysis of ERDA data, it is concluded that the oxygen content of the thin films remains constant and no stoichiometric changes are observed with increasing Ag ion irradiation dose ∼1012 ions/cm2. [Copyright &y& Elsevier]

Ionoluminescence (IL) and photoluminescence (PL) of aluminum silicates irradiated with 100 MeV swift Ni+8 ions with fluences in the range 7.5×1010–1.0×1014 ions/cm2 have been studied. A pair of IL bands with peaks at ∼775 and 875 nm are recorded in both natural crystalline and pelletized kyanite samples. And, a pair of sharp as well as strong PL emission bands with peaks at ∼688.7 and 705.9 nm along with a broad emission band in the region 710–900 nm are recorded in these samples with an excitation of 442 nm laser beam. It is found that both IL and PL intensities decrease with increase of ion fluence. The decrease of IL is attributed to amorphization of the material. [Copyright &y& Elsevier]

Thermoluminescence (TL) of natural kyanite single crystals bombarded with 100 MeV Si+8 ions with fluences in the range 1×1011–5×1013 ions/cm2 has been studied at room temperature (RT). Two TL glows, a medium one at ∼445 K and another intense one at ∼550 K are recorded in single crystals of kyanite. However, in the case of pelletized samples, similar TL glows but with peaks at ∼475 and 615 K, respectively, are recorded at a warming rate of 20 K/min. It is found that as the fluence of Si+8 ion increases, the TL intensity increases. It is also found that the characteristic TL glow peaks appear at higher temperature side in pelletized kyanite than those in crystalline ones, however, the glow peak temperatures remain steady in a given system irrespective of the ion dose. The enhancement in TL intensity and shifting of TL glow peaks to higher temperature side in pelletized kyanite samples are attributed to the particle nature of the phosphor and/or pressure-induced defects in the phosphor. [Copyright &y& Elsevier]