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  Smekhova, A.; Szyjka, T.; La Torre, E.; Ollefs, K.; Eggert, B.; Coester, B.; Wilhelm, F.; Bali, R.; Lindner, J.; Rogalev, A.; Többens, D.; Weschke, E.; Luo, C.; Chen, K.; Radu, F.; Schmitz-Antoniak, C.; Wende, H.: Irradiation-induced enhancement of Fe and Al magnetic polarizations in Fe₆₀Al₄₀ films. New Journal of Physics 24 (2024), p. 023036/1-15

10.1088/1367-2630/ad1497
Open Accesn Version

Abstract:
The rise of Fe magnetic moment, changes in Al electronic structure and a variation of Al magnetic polarization in thin films of transition metal aluminide Fe60Al40 have been probed through the order-disorder phase transition by soft x-ray absorption spectroscopy and x-ray resonant magnetic reflectivity in the extreme ultraviolet regime. In a course of the transition induced by 20 keV Ne+ irradiation with low fluences (∼1014 ions cm−2), x-ray magnetic circular dichroism spectra taken at the Fe L_2,3 absorption edges at room and low temperatures revealed a pronounced increase of Fe 3d states spin-polarization. X-ray resonant magnetic reflectivity applied to the Al L_2,3 and Fe M_2,3 edges allowed to detect the magnetic polarization of Al atoms in the films. The changes in Al electronic structure have been seen by alteration of Al K edge x-ray absorption near edge structure. A difference in anisotropy fields for films before and after irradiation has been observed by element-specific hysteresis loops recorded at low temperatures in absorption and reflection geometries at the Fe L_2,3 and M_2,3 edges, respectively. An attempt to reduce the top oxide layer by an inductively coupled hydrogen plasma has shown a possibility to recover the chemically ordered phase.