Giant magnetoresistance and super-paramagnetism in electrodeposited NiFe/Cu multilayers

The giant magnetoresistance of electrodeposited NiFe/Cu multilayers from a single bath under potentiostatic control is studied. The observed nonsaturating behavior urged us to investigate the probability of the occurrence of superparamagnetic regions in these multilayers. In this research, for the first time, the presence of super-paramagnetic regions in electrodeposited NiFe/Cu multilayers is shown and proved via high resolution transmission electron microscopy. The reason was found to be the existence of a very large anodic transient at the beginning of the copper deposition pulse, which could be eliminated by choosing a more negative potential.