Magnetization dependence of magnetoresistance inCuMnspin-glasses

It is shown that the negative transverse magnetoresistance varies as the square of the bulk magnetization over a wide range of temperature and magnetic field in $\mathrm{Cu}\mathrm{Mn}$ (0.7 and 4.4 at.%) spin-glasses. The constant of proportionality $\alpha$ is independent of field and is weakly dependent on temperature. This is in contrast to the strong, monotonically decreasing $\alpha$ with increasing temperature reported earlier by Schmitt and Jacobs. These results are discussed in the light of the present theories.