Internal Magnetic Fields at Pt Nuclei in Pt-Fe Alloys

The M\"ossbauer effect of the 99-keV, 3/2^--to-^- transition in Pt¹⁹⁵ has been measured, using a single-line source of Au¹⁹⁵ in Cu and ferromagnetic Fe-Pt alloy absorbers. The internal field at the Pt nucleus, Hᵢₙₜ(Pt), in the alloy absorbers was determined and found to be nearly constant, about 1.26×{}10⁶ Oe, over a range of composition from 3 to 30 at.% Pt. Hᵢₙₜ(Pt) for an Fe0.50{Pt}0.50$ alloy absorber and for a source (${Au}¹⁹⁵→{Pt}¹⁹⁵$ in Fe) are smaller, ${H}ᵢₙₜ(Pt){}1.0×{}{10}⁶ and 0.85×{}{10}⁶$ Oe, respectively. The $g$ factor of the state is found to be -0.40±{}0.10 nm.