Positive magnetoresistance due to impurity interactions in dilute AuCr alloys

The magnetoresistance of dilute AuCr alloys (2.3–322 at.ppm) has been measured in a wide region of temperature (5-3K) and of magnetic field (up to 60 kG).The “modified Kohler's rule” was used to extract the spin dependent magnetoresistance (?_M) from measured total magnetoresistance.The results has shown that, except for the most dilute specimen, ?_M includes explicitly a positive component in addition to the ordinary negative magnetoresistance proportional to log (H/T). We have attributed this positive ?_M to the effect of the interactions between the Cr impurities by taking consideration of the generalized phase shift expression of magnetoresistance proposed by Soultie.