Temperature dependence of the giant magnetoresistance in Fe–Cr multilayers—Intralayer and interlayer exchange energies

We present field and temperature dependence data on giant magnetoresistive (GMR) ion-beam sputtered Fe–Cr multilayers of varying Cr thickness. We show that the decrease in GMR with temperature is related to the decrease in sublattice magnetization due to thermal excitation of magnons in the antiferromagnetic configuration. The intralayer and the interlayer exchange energies thus obtained vary systematically as the Cr thickness increases. The corresponding decrease in the measured saturation field further supports our interpretation leading to a better understanding of the physics of GMR.