Mössbauer Spectroscopy Evidence for Phase Selectivity in Excimer Laser Induced Amorphization of Thermally Annealed FeCoBSi Metallic Glass

Pulsed excimer laser irradiation effects (λ = 308 nm, τ = 10 ns, w = 3 J/cm² , N = 2 laser pulses/spot, repetition rate 1 Hz) on the magnetic properties and phase composition of thermally annealed Fe₆₆Co₁₈B₁₅Si₁ metallic glass have been studied by transmission and conversion electron Möss-bauer spectroscopy (CEMS). Radiation-driven surface modifications were examined by scanning electron microscopy (SEM). Excimer laser induced amorphization was observed in partially crystallized Fe₆₆Co₁₈B₁₅Si₁ samples (T _A = 648 K, t _A = 1 hour) and was found to be accompanied by the development of laser-induced magnetic anisotropy. In totally crystallized Fe₆₆Co₁₈B₁₅Si₁ specimens (T A = 723 K, = 1 hour), the effect of excimer laser induced amorphization exhibited phase selectivity with respect to the crystalline components of the alloy system. When compared to bulk data, a different behavior of the surface magnetic texture and relative abundance of alloy phases was observed. The laser-induced phase transformation of thermally annealed Fe₆₆Co₁₈B₁₅Si₁ specimens was shown to consist of partial amorphization and surface oxidation of the irradiated material.