Magnetic properties of amorphous (Fe1-xMnx)78B22 alloys

Abstract Amorphous (Fe 1- x Mn x ) 78 B 22 ( x ⩽ 0.4) alloys have been prepared by melt quenching technique and their magnetization measurements have been made over the temperature range from 77 to 800 K. The observed ratio of the spin-ware stiffness constant to the Curie temperature 0.15 meV A -1 is nearly independent of Mn concentration, from which the localized electron nature characterizing the nearest neighbor interaction is preferred in the present alloys. On the basis of the Curie temperature and the average magnetic moment, it is emphasized that the antiferromagnetic coupling between Mn atoms, as well as the environmental effect around some Fe or Mn atom begins to play an important role with increasing Mn concentration especially near the critical concentration at which ferromagnetism disappears.