Transient thermal process induced by swift heavy ions: Defect annealing and defect creation in Fe and Ni

Abstract

In the present paper, a method is proposed to quantitatively estimate the nuclear defect annealing by the electronic stopping power S. The spatial distribulion of defects created in metals by nudear collisions is known from numerical calculation based on the binary collisions with screened Coulomb potential. In the framework of the thermal spike model, S~ induced annealing of nuclear defects is simulated without considering athermal recombination. These calculations are applied to iron and nickel. The agreement between experiment and simulation in iron allows to determine the electron-phonon coupling value for iron. The defect creation by S e arises when the energy deposited on the atoms overcomes the energy necessary to melt the material.

Material Transformation: Interaction between Nuclear and Electronic Energy Losses

“…Such competitive phenomenon was also observed in SiC [12,13] by sequential irradiations. [1], Nd (black line) the calculated number of defects from binary collision approximation BCA [7], Nda (black dotted line) is the number of defects after annealing process by the electronic energy loss [7,8], Ndac (blue dotted line) is equal 0.43×Nda [8]. (b) Density of defects [7,8] versus radial distance R from the ion path before (Ndi(R), (full black line) and after annealing (Nda(R) (red dotted line).…”

“…1b). The total number of stable defects after annealing (N da ) is calculated [1,7] for all the irradiations by integrating over R and compared to the experimental results [6] (Fig. 1a).…”

“…The calculations lead to a decrease of the number of defects (N da ) versus S e like in the experiment. Multiplying N da by 0.43 [1] to normalized N da to the experimental points, it is possible to describe the experiment. This factor can be qualitatively explained as the annealing of defects created within the recombination volume [11].…”

“…Within the framework of the inelastic thermal spike model (i-TS) [8,9], it is supposed that the energy deposited by S e on the electrons is thermalized by electron-electron interactions before its transfer to the lattice, leading to a short and significant increase of the lattice temperature. The initial radial distribution of the defects (N di (R)) versus radial distance from the ion path was calculated by Wang et al [7] and a thermal process induced by S e is superimposed on this radial distribution [1] (Fig. 1b).…”

“…the addition is larger than the sum of the two (1+1>2). In order to exemplify the different cases, the results of four separate experimental investigations are resume in the present paper, including model descriptions: 1) defects created by nuclear collisions in Fe and annealed by electronic excitations with GeV ions demonstrates the competitive interaction [1]; 2) the atomic sputtering of Ti induced by ions of ~100 MeV showing a synergistic effect [2]; and 3) damage formation in crystalline [3] and amorphous [4] SiO 2 demonstrates a clearly cooperative interaction and possibly additive. The details of the four experiments [1][2][3][4] and the applied model descriptions [1,2,4,5] are presented and discussed in the original papers .…”