Swift heavy ion irradiation-induced amorphous iron and Fe-Si oxide phases in metallic Fe-57 layer vacuum deposited on surface of SiO2/Si

AbstraktAbstract

Fe-57 conversion electron Mossbauer (CEM) spectroscopy, SEM and magnetization measurements were used to study the effect of swift heavy ion irradiation on metallic Fe-57 (10 nm) thin layer vacuum deposited onto SiO2/Si. About 85% of the total iron content of the surface layer detected by CEM was present as metallic, crystalline alpha iron before the irradiation, while upon irradiation with 160 MeV Xe ions, with a fluence of 5 x 10(13) ion cm(-2), similar to 21% was converted to amorphous iron and similar to 47% to silicon-containing iron oxide phases. The presence of pure iron in the amorphous state was evidenced by CEM in agreement with magnetization measurements. Temperature dependence of CEM measurements and the FC/ZFC curves of the irradiated deposit indicated superparamagnetic nature of the iron-silicon-oxide phases. The results are discussed in terms of the thermal spike model for the formation of the amorphous iron phase that can be essential for the formation of silicon-iron-oxides.

Fe-57 conversion electron Mossbauer (CEM) spectroscopy, SEM and magnetization measurements were used to study the effect of swift heavy ion irradiation on metallic Fe-57 (10 nm) thin layer vacuum deposited onto SiO2/Si. About 85% of the total iron content of the surface layer detected by CEM was present as metallic, crystalline alpha iron before the irradiation, while upon irradiation with 160 MeV Xe ions, with a fluence of 5 x 10(13) ion cm(-2), similar to 21% was converted to amorphous iron and similar to 47% to silicon-containing iron oxide phases. The presence of pure iron in the amorphous state was evidenced by CEM in agreement with magnetization measurements. Temperature dependence of CEM measurements and the FC/ZFC curves of the irradiated deposit indicated superparamagnetic nature of the iron-silicon-oxide phases. The results are discussed in terms of the thermal spike model for the formation of the amorphous iron phase that can be essential for the formation of silicon-iron-oxides.