The negative-muon spin-precession technique was used to study the hyperfine field at the negative muon ${\mu }^{\mathrm{-}}$ in ferromagnetic iron in zero applied magnetic field. In the temperature range 320–690 K the hyperfine field for ${\mu }^{\mathrm{-}}$Fe departs from the magnetization curve of pure iron in the same way as the hyperfine field acting upon a ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$ impurity in dilute (1.5 at.%)MnFe measured by NMR, indicating that the electronic structure of ${\mu }^{\mathrm{-}}$Fe is very similar to that of a Mn impurity in iron. The hyperfine anomaly Δ for ${\mu }^{\mathrm{-}}$Fe relative to dilute (1.5 at.%${)}^{55}$Mn in iron is found to be -0.9(3)% and temperature independent over the temperature range investigated. The magnitude of Δ is considerably smaller than that of our value Δ=-2.5(4)% for ${\mu }^{\mathrm{-}}$Ni relative to ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$ in ferromagnetic nickel.

• Received 15 May 1986

DOI:https://doi.org/10.1103/PhysRevB.35.2008