Mössbauer spectroscopy of 61Ni

Abstract

The Mössbauer effect of ⁶¹Ni has been observed using a single line source, prepared by 100 min LINAC irradiation. Of the many sources evaluated, a ⁶²NiCr (15%) gave the best results, with a ƒ-factor of 0.1 and a linewidth of 0.097 cm/sec at 80°K. The source was activated by 100 MeV bremsstrahlung radiation using the ⁶²Ni(γ,p)⁶¹Co reaction. The pulse height spectrum showed a single peak at 67.3 keV, with no interfering radiation. The 1.7 h half-life of the source required repeated irradiations, but annealing was not required.

Several alloys and compounds of nickel were examined, and showed partially resolved hyperfine interactions. The chemical shift is small for nickel compounds. The magnetic moment of the 5/2 spin 67.3 keV state is +0.425 ± 0.043 nm, measured from the magnetic hyperfine interaction of a FeNi (1.5 %) alloy. Quadrupole splitting of the 5/2 state was observed in (NH₄)₆[Ni_IVMo₉O₃₂].