Sublinear temperature dependence of resistivity in metallic heterogeneous ferromagnets at high magnetic fields

The high field resistivity of metallic Co-Ag films is found to follow the unusual sublinear ($d\rho /dT<\mathrm{}1\mathrm{}$) temperature dependence. The effect is argued to be caused by a strongly enhanced electronic scattering by small magnetic moments embedded in the matrix of the macroscopically magnetized heterogeneous ferromagnet. The mechanism is shown to be an important contribution to the giant magnetoresistance effect and is relevant for both granular and multilayered systems with frozen or loose magnetic moments.