Reevaluation of spin-dependent cross sections of solutes in Fe

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Abstract
The resistivity data of Fe‐based ternary alloys has been reevaluated taking into account that the conduction electrons in Fe are predominantly highly polarized (∼95%) d‐like electrons. This drastically changes the previously derived values of solute cross sections and scattering rate ratios of the majority and minority conduction electrons. It further removes the perplexing result of previous analyses that the spin‐up and spin‐down cross sections of sp solute atoms were not equal but varied by about a factor of 7. These cross sections should be equal since the nonmagnetic sp electrons cause only a charge perturbation. The vastly different cross‐section ratios from those previously obtained cast doubt on the proposed explanation of the giant magnetoresistance effect as being due to spin‐dependent scattering from solute or interface atoms. A more plausible explanation of the large magnetoresistance at low fields for both pure Fe and its layered structures is that it is caused by the large scattering at antiparallel magnetic boundaries due to the high polarization of the conduction electrons. Moreover, since past analyses of scattering, transport effects, etc. in 3d ferromagnetics have assumed that the conduction electrons are sp‐like, all of these results should also be critically reexamined to determine their validity.