Giant magnetoresistance in Fe/In multilayers and its anomalous temperature dependence

Fe/In multilayers were prepared by the DC magnetron sputtering method, and their electrical and magnetic properties were studied. Negative giant magnetoresistance (GMR) with a maximum of −0.84% at 10 K was observed. The magnitude of GMR and the saturation field (Hs) were found to oscillate with a period about 1.3 nm when varying the thickness of In layers. Atomic force microscope images of samples were taken to investigate the surface morphology. The GMR effect is composed of antiferromagnetic coupling between the neighboring Fe layers and superparamagnetic spins effect at the Fe/In interface. A reduction of the anomalous GMR effect with decreasing temperature is presented.