Effect of Nitrogenation and Hydrogenation on the Magnetic Properties and Structure of the Sm2Fe17 Alloy: Analysis of XMCD Data

Resumo

Changes in the local magnetic and structural properties of Sm₂Fe₁₇ alloys at nitrogenation and hydrogenation of samples have been studied by the X-ray magnetic circular dichroism (XMCD) technique at the Fe K absorption edge and Sm L₃ absorption edge using synchrotron radiation. The results have been discussed in comparison with X-ray diffraction data and macroscopic vibration magnetometry measurements. The observed changes in XMCD spectra indicate a noticeable effect of nitrogenation on the local magnetic properties of sublattices of both iron and samarium, whereas hydrogenation of samples makes a small effect. The mentioned effects have been analyzed and discussed in terms of the effect of nitrogen (N) and hydrogen (H) interstitial atoms on Sm 5d and Fe 4p electronic states. The effect of nitrogenation is larger than the effect of hydrogenation because the volume expansion of the crystal lattice of initial Sm₂Fe₁₇ in the case of nitrogenation is larger than that in the case of hydrogenation. The studied local magnetization curves for samarium and iron sublattices in magnetic fields up to 17 T also indicate a strong increase in the magnetocrystalline anisotropy at nitrogenation.