The use of a thermal spike model for temperature calculation in two-layer structures along the projective track of a high-energy heavy ion

Experimental study and thermal spike modeling of sputtering in SiO2 thin films under MeV Auq+ heavy ion irradiation

“…Then, we solved numerically the two nonlinear Equations and by using an explicit finite difference method, as previously proceeded, 11,12 with the condition of convergence, , where the time and radial steps (Δ t , Δ r ) are assumed appropriately to amount to ~10 −16 s and ~0.2 nm, respectively. Also, the boundary conditions (ambient temperatures) for the electronic and atomic subsystems in regions far from the ion path (i.e., for r → ∞) are assumed 42 to be T e = T a = 300 K. On the other hand, the specific heat and thermal conductivity are taken in the present work from the fit to their corresponding experimental and numerical values in case of SiO 2 thin films 43–50 with thicknesses close to that used in the present experiment. Indeed, the dependence of thermophysical properties on SiO 2 film thickness has been previously well investigated through several experimental and theoretical works 43–50 .…”

High Density Cobalt Nanostructures by Ion Beam Induced Dewetting

“…This is also suggested from experimental results on ion beam mixing in metals, where metals of comparable size like Cu and Ni have very different mixing behavior [23,24]. These earlier papers suggested that the loss of energy to the electrons of the target and the subsequent electron-phonon coupling plays a crucial role in energy transfer when ion beams interact with solids, and this has continued to motivate efforts to model this process [25,26].…”

“…Assuming even distribution of kinetic energy within the region, and considering that thermal energy at 300 K corresponds to about 40 meV, the transient temperature may be estimated to be of the order of 10 3 -10 4 K. The SRIM simulations for a 100 keV Ar ions in Co give a figure of about 1400 eV/nm as the energy loss to target atoms throughout the thickness of the film. There are also estimates from the literature of the thermal spike in metals, ranging from several hundred K to several thousand K [25][26][27], depending on the value of the electron-phonon coupling parameter, which is involved in the transfer of energy from the electronic to the lattice subsystems and on whether the model of lattice relaxation used was linear or non-linear. At this point, a more accurate estimate awaits full molecular dynamics calculations for more substantial periods or the development of experimental techniques which allow access to phenomena at shorter time scales.…”