Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 26: Thin Films: Magnetic Coupling Phenomena / Exchange Bias

MA 26.7: Vortrag

Dienstag, 21. März 2017, 15:30–15:45, HSZ 101

Evolution of the local environment and magnetism in Fe₆₀Al₄₀ films under Ne⁺ irradiation — •A. Smekhova^1,2, E. La Torre², B. Eggert², B. Cöster², Th. Szyjka², D. Walecki², S. Salamon², K. Ollefs^2,3, R. Bali⁴, J. Lindner⁴, A. Rogalev³, E. Weschke⁵, R. Banerjee⁶, B. Sanyal⁶, C. Schmitz-Antoniak¹, and H. Wende² — ¹FZ Juelich (PGI-6), Berlin — ²University of Duisburg-Essen and CENIDE, Duisburg — ³ESRF, Grenoble — ⁴HZDR, Dresden — ⁵HZB (BESSY II), Berlin — ⁶Uppsala University, Uppsala

X-ray absorption spectroscopy has been applied to study the consequential changes of the local environment around Fe and its magnetic moments in Fe₆₀Al₄₀ thin films of 40 nm thickness along the order-disorder (B2 → A2) phase transition initiated by 20keV Ne⁺ ion-irradiation with fluences of (0.75-6)×10¹⁴ ions·cm⁻². The analysis of EXAFS spectra measured at the Fe K-edge at room temperature revealed an increased number of Fe-Fe nearest-neighbors from 3.47(7) to 5.0(1) and ∼1% of volume expansion through the transition. The visualization of the Fe and Al nearest-neighbours rearrangement in the first coordination shell of Fe absorbers was done by wavelet transformations. The observed structural changes will be related to the magnetic properties of the studied samples. The results of self-consistent DFT calculations using VASP and SPR-KKR program packages on relaxed Fe₆₀Al₄₀ structures are consistent with the experimental findings for the ordered (B2) and the disordered (A2) phases.