Determination of the Kondo Temperature and Internal Field Distribution in DiluteAuMnAlloys

The resistivities of several $\mathrm{Au}\mathrm{Mn}$ alloys, containing between 0.005 and 1.5 at.% Mn, have been measured in the temperature range 0.5-40°K. The magnitude of the spin resistivity is determined from the decrease in resistance due to ordering in internal fields. This, combined with a measurement of the coefficient of the logarithmic term in the resistance at temperatures well above the resistance maximum, allows the Kondo temperature to be determined, the value so obtained being of the order of ${10}^{-13\mathrm{}}$°K. The predicted resistivity at $T=0\mathrm{}$, in the absence of interactions, is shown to be comparable with the unitarity limit for $d$-wave scattering. Information is also obtained concerning the magnitude and distribution of internal fields within the alloys. The distribution is found to approximate to a Gaussian, but with a dip in the region of very low fields.