Evolution of phases and microstructure inFe81B13.5

Abstract

A comparative study of electron-beam and pulsed-laser irradiation effects in metallic glasses has been performed in order to understand the relationship between magnetic behavior and select variations in the structural characteristics of alloy phases. Samples of FegiB, 3 5Si3 5C2 metallic glass were irradiated with a pulsed excimer laser (A, = 308 nm,~= 10 ns), with a high-energy electron beam ( 8 = 7 MeV), and with low-energy electron beams (8'=30 and 50 keV). Irradiation-driven changes in the magnetic anisotropy and phase equilibrium of alloy samples were studied by Mossbauer spectroscopy and scanning electron microscopy. Complementary information was obtained using energy-dispersive x-ray analysis. High-energy electron-beam irradiation was found to induce an out-of-plane magnetic anisotropy due to changes in the chemical short-range order. Low-energy electron-beam irradiation resulted in the formation of crystalline regions, in which a-Fe, Fe-Si, Fe,B, Fe2B, and clusters of y-Fe were identified. Interpretation of these results is given in terms of radiation-enhanced diffusion. Pulsed-excimer-laser irradiation was found to induce controlled magnetic anisotropy without onset of bulk crystallization in the Fe8lBl3 5S13 5C& amorphous system. The effect of excimer-laser-induced amorphization was evidenced in thermally annealed Fe81B&3 5S13 5C2 samples and explained using melt model calculations. In all cases studied, the key to explaining the irradiation-induced property modifications is the underlying alloy micro structure.

Magnetism and recoilless fraction in metallic glasses after laser irradiation

“…[5][6][7][8]. This behavior is consistent with some previous findings [1][2][3][4]. Indeed, it follows that the in-plane compressive stresses associated with the laser irradiation have caused atomic spins to rotate in a direction normal to the sample surface.…”

“…Consequently, the calculated values of the magnetic texture parameter R 21 (see also Fig. 9) show that the magnetic moments of the as-prepared material are preferentially oriented in the plane of the ribbon sample, as observed for other amorphous alloys with similar compositions [1][2][3][4]. Fig.…”

“…The solid line in Figs. 1-8 represents the nonlinear least-squares fitting using a histogram method [2]. In all cases, the "goodness of fit" criterion χ 2 was close to unity.…”

“…Improved thermal stability and different crystallization kinetics have been shown to characterize the effect of ultrashort pulse laser irradiation in several binary amorphous alloys [1][2][3][4][5][6][7][8]. Pulsed excimer lasers offer improved beam homogeneity, better pulse-to-pulse shape and energy density reproducibility and the possibility of employing high repetition rates even at high pulse energies.…”

Response of strontium titanate to electron irradiation for the immobilization of strontium

“…In order to assess the long-term stability of radwaste forms, a number of investigations have focused on the radiation tolerance, and showed that irradiation induced the phase segregation in alloys and glass [8][9][10]. 90 Sr is a highly radiotoxic fission product, the decay of the strontium emit beta particles with energy E 0.546 and 2.28 MeV.…”