Magnetoresistance in heavy-fermion alloys.

TLDR: The spin-flip scattering of an electron by a pair of adjacent magnetic impurities is calculated in the presence of a magnetic field and yields an interesting field dependence for the magnetoresistance at various temperatures and may cause a change of sign in the magnetorsistance as well as in the Hall effect.

Abstract: The spin-flip scattering of an electron by a pair of adjacent magnetic impurities is calculated in the presence of a magnetic field. In the limit of zero field the pair scattering yields a sharp drop in the low-temperature resistivity whose strength is inversely proportional to T. This process provides an explanation for the anomalous drop in resistivity below T\ensuremath{\le}100 K for ${\mathrm{UPt}}_{3}$ and many other heavy-fermion alloys. An external magnetic field is shown to quench this spin-flip contribution, resulting in a positive magnetoresistance for ${\mathrm{UPt}}_{3}$ at low temperatures. In conjunction with the single-impurity Kondo scattering, the pair process yields an interesting field dependence for the magnetoresistance at various temperatures and may cause a change of sign in the magnetoresistance as well as in the Hall effect.