Sputtering of vitreous SiO2 and Y3Fe5O12 in the electronic stopping power region. A thermal spike description

The thermal spike model was applied to calculate track radii versus electro nic stopping power for different beam energies using only one fitting param eter, lambda the mean diffusion length of the energy deposited on the elect rons by the slowing down of a swift heavy ion in vitreous silica a-SiO2. A A value of 2.5 +/- 0.2 nm is extracted by fitting all the different results of damage creation taking into account a velocity effect. Using the same v alue of lambda, the energy necessary to vaporize the vitreous silica is rea ched for lambda value of electronic stopping power dE/dr, which corresponds to the appearance of a huge sputtering of silicon in SiO2. So in the therm al spike model one can explain two phenomena with the same value of the fre e parameter lambda. The present paper aims at extending this model to the y ttrium iron garnet Y3Fe5O12, abbreviated as YIG. By fitting the latent trac k radii one can extract the unique following values: R = 5.0 +/- 0.3 nm and a latent heat of fusion LH = 300 +/- 100 J g(-1). Then the energy value L- v of 2.2 +/- 0.4 eV/atom necessary to sputter this material is extracted. T he evolution of sputtering yield versus the electronic stopping power is in good agreement with the experimental results, (C) 1998 Elsevier Science B. V. All rights reserved.