REEVALUATION OF SPIN-DEPENDENT CROSS-SECTIONS OF SOLUTES IN FE

The resistivity data of Fe-based ternary alloys has been reevaluated t aking into account that the conduction electrons in Fe are predominant ly highly polarized (approximately 95%) d-like electrons. This drastic ally changes the previously derived values of solute cross sections an d scattering rate ratios of the majority and minority conduction elect rons. It further removes the perplexing result of previous analyses th at the spin-up and spin-down cross sections of sp solute atoms were no t equal but varied by about a factor of 7. These cross sections should be equal since the nonmagnetic sp electrons cause only a charge pertu rbation. The vastly different cross-section ratios from those previous ly obtained cast doubt on the proposed explanation of the giant magnet oresistance effect as being due to spin-dependent scattering from solu te or interface atoms. A more plausible explanation of the large magne toresistance 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. i n 3d ferromagnetics have assumed that the conduction electrons are sp- like, all of these results should also be critically reexamined to det ermine their validity.