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The present work reports the effects of 120 MeV Au9+ on structural and electronic properties of polycrystalline SnO2 films of about 170 nm thickness prepared by spin-coating. 119Sn Mössbauer measurements are used to probe the electronic properties. The observed isomer-shift values clearly indicate Sn4+ for the pristine sample and its progressive reduction to Sn2+ and eventually to the metallic Sn state at higher fluence values. These observations are corroborated by x-ray diffraction, Raman, and x-ray photo-electron spectroscopy measurements. The x-ray diffraction measurements indicate the complete amorphization of the tin oxide phase, while the recrystallization of the metallic Sn phase with irradiation. The optical bandgap is observed to vary with ion beam irradiation. The observations indicate the possibility of tuning the electronic configuration of Sn in tin oxide thin films with swift heavy ion beam irradiation, and the results are explained in terms of the thermal-spike model of swift heavy ion irradiation. [ABSTRACT FROM AUTHOR]

Swift heavy ions induced structural and magnetic modifications of Co/Ti multilayers have been studied with 120 MeV Ag9+ ions at different ion fluences. The decrease in 1st Bragg peak intensity of X-ray reflectivity spectra confirms an increase in Co-Ti mixing at the interfaces, whereas X-ray diffraction (XRD) measurements reveal amorphization of the crystalline Co layer. XRD also indicates a shift in peak position towards a lower angle, confirming the development of tensile stress upon irradiation whereas an increase in the peak width suggests the reduction in the grain size. Vibrating sample magnetometer measurements show a reduction in Mr/Ms due to Co-Ti interface mixing and formed bcc-Co3Ti metastable phase. The X-ray absorption fine structure (XAFS) technique has been utilized to obtain variation in Co-Co and Co-Ti bond distances as a function of ion fluences. Quantitative estimation of Co3Ti phase generated due to ion irradiation has also been obtained using Co K-edge XAFS fitting. [ABSTRACT FROM AUTHOR]

The quality of organic semiconductor tris-(8-hydroxyquinoline)aluminum (Alq3) thin films, deposited at the rate of 5.0 Ĺ s−1, 2.5 Ĺ s−1, and 1.0 Ĺ s−1 respectively, have been investigated using x-ray reflectivity (XRR) and grazing incidence small angle x-ray scattering (GISAXS) studies. While XRR provides information about structural details, GISAXS provides information about the morphology of the films. The film quality is very good with a surface roughness of only 8 Ĺ. The electron density of the film increases from 0.39 e Ĺ−3 to 0.43 e Ĺ−3 due to reduction of growth rate from 5 Ĺ s−1 to 1 Ĺ s−1. The higher electron density (0.43 e Ĺ−3) of the film deposited at the lower deposition rate (1 Ĺ s−1) indicates the presence of less defects and/or porosity in the film. Average separation between pores increases from 200 Ĺ to 500 Ĺ and simultaneously pore depth decreases from 300 Ĺ to 120 Ĺ due to reduction of growth rate from 5 Ĺ s−1 to 1 Ĺ s−1. The mixing between Alq3 and Co at the Alq3/Co interface and diffusion of Co into Alq3 layer through Co/Alq3 interface have been studied by combined XRR and grazing incidence x-ray standing wave (GIXSW) measurements for the three Alq3/Co/Alq3/W/Si multilayers in which Alq3 films were deposited at the above mentioned three different rates. It is found that there is about 30 Ĺ thick (∼ two monolayer of Alq3) mixing region at the Alq3/Co interface in three multilayer samples, which suggests that mixing at this interface is independent of the growth rate of Alq3 films. The depth of diffusion of Co into Alq3 through Co/Alq3 interface reduces from 300 Ĺ to 160 Ĺ due to the reduction of deposition rate from 5 Ĺ s−1 to 1 Ĺ s−1. This study suggests that by controlling the growth rate of Alq3, porosity as well as the diffusion of ferromagnetic Co in an organic semiconductor Alq3 can be reduced, which plays an important role in the performance of organic spin valve devices. [ABSTRACT FROM AUTHOR]