Temperature dependence of magnetoresistance in Fe-Cr-Fe sandwiches

Abstract

Resistivity measurements have been performed as a function of temperature (1–300 K) and magnetic field (0–10 T) on antiferromagnetically coupled Fe-Cr-Fe sandwiches. Two types of samples were studied: MBE-grown sandwiches deposited epitaxially on the ZnSe (100) surface, and evaporated polycrystalline sandwiches deposited on glass substrates. The magnetic saturation field Hs determined from the resistivity ρ(H,T) is linear with temperature throughout the full temperature range for all samples. In the polycrystalline sandwiches, where the observed in-plane magnetic anisotropy is small, the linearity of Hs(T) implies that the antiferromagnetic interlayer exchange coupling A12 is also linear with temperature. The magnetoresistance of the sandwiches is constant at low temperature, and decreases linearly with increasing temperature above about 70 K.