Resistivity, magnetoresistance and Hall effect of FexGe1−x amorphous alloys

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Abstract
The resistivity ρ, the transverse magnetoresistance and the Hall resistivity ρH have been measured in the amorphous FexGe1−x alloys for x from 0.1 to 0.6. The resistivity always decreases when T and x increases and is not sensitive to the appearance of magnetism. It is interpreted with a model requiring a mobility in the upper tail of the band where transport takes place. There is an Anderson transition around x = 0.5. We measure an isotropic negative magnetoresistance for 0.3<x<0.45 to which is superposed, for x≳0.45, an anisotropic negative magnetoresistance. The ordinary Hall effect is positive and independent of T. For x≳0.3, a term of anomalous Hall effect is added. Both effects have a particular behaviour due to the increase of the carriers localisation in these alloys.