Giant magnetoresistance in permalloy/copper multilayers

The oscillatory behaviour of the giant magnetoresistivity versus Cu sublayer thickness was observed in Ni83Fe17/Cu multilayers with an oscillation period of 1 nm independently of buffer layer and substrates used in the experiment. The giant magnetoresistance field sensitivity equal to 0.02%/Oe and 0.15%/Oe for the first and the second maximum respectively, were found. It was shown that the giant magnetoresistance effect in our multilayers is not only due to the antiferromagnetic coupling between adjacent permalloy layers but also due to the superparamagnetic-like behaviour related to the existence of the intermixed interfacial areas.