Magnetic properties of iron-rich Fe-Sc glasses

Abstract

Amorphous ${\mathrm{Fe}}_{\mathrm{x}}$${\mathrm{Sc}}_{100\mathrm{\ensuremath{-}}\mathrm{x}}$ alloys with x=89, 90, and 91, prepared by melt spinning, exhibit a single sharp spin-freezing transition at 100\ifmmode\pm\else\textpm\fi{}3 K to an asperomagnetic state. The average $^{57}\mathrm{Fe}$ hyperfine field at 4.2 K is 22.7 T. Magnetization curves indicate that fields in excess of 20 T would be required to achieve saturation at 4.2 K and that the iron moment extrapolated to infinite field is 1.6${\ensuremath{\mu}}_{B}$. Hysteresis is found at low temperatures. On hydrogenation, the alloys become soft collinear ferromagnets with an iron moment of 2.2${\ensuremath{\mu}}_{B}$ and a Curie point of 310 K. A magnetic phase diagram is presented that summarizes the magnetic properties of a-${\mathrm{Fe}}_{\mathrm{x}}$${\mathrm{M}}_{100\mathrm{\ensuremath{-}}\mathrm{x}}$ systems (M=Sc,Y,Zr, or Hf). The behavior when M is a IIIb element (Sc,Y) is distinct from that when it is a IVb element (Zr,Hf), suggesting that the direct iron-iron exchange is frustrated by an indirect antiferromagnetic coupling in the IIIb alloys. Both groups tend to a common limit as x\ensuremath{\rightarrow}100. .AE