Spin-Disorder Scattering in Iron- and Nickel-Base Alloys

The electrical resistivities of iron-base alloys with Cr, W, Mn, Ru, Co, Ni, Si, or Ge solutes, and of nickel-base alloys with Cr, Fe, Cu, or Pd solutes were measured from 4.2 \ifmmode^\circ\else\textdegree\fi{}K to above the Curie temperatures $\ensuremath{\theta}$. The solute resistivities ${\ensuremath{\rho}}_{r}(T)[={\ensuremath{\rho}}_{\mathrm{alloy}}(T)\ensuremath{-}{\ensuremath{\rho}}_{\mathrm{host}}(T)]$ were found to be strongly temperature dependent. Above \ensuremath{\sim} 300 \ifmmode^\circ\else\textdegree\fi{}K, the temperature dependence of ${\ensuremath{\rho}}_{r}(T)$ reflects changes in the electronic structure or in the scattering processes associated with the solutes and is related to changes in the magnetic order. The solute resistivities above 300 \ifmmode^\circ\else\textdegree\fi{}K were found to be in reasonable agreement with a spin-disorder model which explicitly involves the moments localized at the solute sites. Agreement with the well-known Mott band model for ferromagnetic effects in transport properties was not as satisfactory. An essential feature of the analyses of the data involved comparing resistivities of alloy and host corresponding to the same degree of magnetic order. This was accomplished by assuming the ferromagnetic effects in the resistivity scaled as $\frac{T}{\ensuremath{\theta}}$. The experimental results support the validity of this assumption.