Local crystalline structure of Sm-Co alloys: Results of XAFS-analysis

Local crystalline structure of hypo- and hyperstoichiometric SmCo_x alloys with x = 5.15, 4.95, 4.0, 3.75 heat treated in different conditions was investigated by means of the X-ray absorption spectroscopy. Experimental spectra were measured above the L₃-Sm absorption edge. EXAFS-analysis shows that stacking faults appear in hyperstoichiometric alloys SmCo₄ and SmCo_3.75, confirming the hypothesis of "high coercive state, induced by phase transformations, changing the state of the grain surface in basic phase". L₃-Sm XANES spectra demonstrate the reduction of the "white line" amplitude in Sm-enriched samples.