Itinerant Electron Ferromagnetism in Y2Ni7and Mössbauer Effect of57Fe Doped in Y2Ni7

Magnetization of Y 2 Ni 7 and Mössbauer spectra of 57 Fe doped in Y 2 Ni 7 are measured. The paramagnetic susceptibility of Y 2 Ni 7 above 150 K follows the Curie-Weiss law. The ratio of paramagnetic moment to ferromagnetic moment of 0.077 µ B per nickel atom is 6, revealing an itinerant-electron character of ferromagetism in Y 2 Ni 7 . The hyperfine field of 57 Fe doped in Y 2 Ni 7 is ∼190 kOe, which lies on a smooth interpolation curve between the hyperfine field in Y 2 Ni 17 and that in YNi 3 as a function of yttrium concentration in contrast with a re-entrant behavior of a magnetic moment of nickel atom in the compounds.