Preparation, structure and giant magnetoresistance of electrodeposited Fe Co/Cu multilayers

TL;DR

This study investigates the preparation, structure, and giant magnetoresistance properties of electrodeposited Fe-Co/Cu multilayers, optimizing deposition potential and analyzing how layer thickness and composition affect GMR behavior.

Contribution

It provides the first systematic analysis of GMR in electrodeposited Fe-Co/Cu multilayers, including electrochemical optimization and detailed magnetic and structural characterization.

Findings

GMR reaches about 5% at Cu layers above 1.5 nm

GMR decreases with higher Fe content in the magnetic layers

No oscillatory GMR observed with varying spacer thickness

Abstract

No systematic studies have been carried out on the giant magnetoresistance (GMR) of electrodeposited (ED) Fe-Co/Cu multilayers since the elaboration of a method for the optimization of the Cu layer deposition potential. In this paper, we present results on the electrochemical optimization of the Cu layer deposition potential which was found to depend on the relative iron concentration in the bath. An X-ray diffraction study of ED Fe5Co95(1.5 nm)/Cu(dCu) multilayers with dCu ranging from 0.8 nm to 10 nm revealed an fcc structure. For most of the multilayers, a weak superlattice satellite reflection could be identified. The room-temperature magnetoresistance was studied in detail as a function of the individual layer thicknesses. Multilayers with Cu layer thicknesses above about 1.5 nm were found to exhibit a GMR behavior with a maximum GMR of about 5 % and a typical saturation field of 1 kOe. The GMR magnitude decreased with increasing Fe-content in the magnetic layer. The spacer layer thickness evolution of the MR data was established in detail after separating the ferromagnetic and superparamagnetic GMR contributions and no oscillatory GMR was found. A comparison with literature data on both physically deposited and ED Fe-Co/Cu multilayers is also made.