Pressure and temperature dependence of the hyperfine field of Mn and Au in iron

The pressure dependence of the hyperfine field (Hsub(T)) of Mn and Au in iron has been measured to 15 kbar. The values of (dnHsub(T)/dP)sub(T) were found to be (14.9 +- 0.3); (-4.6 +- 0.2); (-1.66 +- 0.02) x 10-4 kbar-1 for Mn, Au and Fe respectively. The large value of (dlnHsub(T)/dP)sub(T) for Mn suggests that a narrow bound state at the Fermi level, rather than a weak localized Mn-Fe exchange interaction, is responsible for the strong temperature dependence of the Mn hyperfine field. The temperature dependence of the hyperfine field of Au in iron may be due to a local lattice mode at the Au site. (orig.)