Structure and giant magnetoresistance effect of Fe/Cu and FeCoNi/Cu multilayers

Abstract

We have studied the giant magnetoresistance (GMR) effect and the film structure of Fe/Cu and FeCoNi/Cu multilayers (MLs), where the FeCoNi alloy is in the composition range of the bcc phase. Both MLs show the oscillation of MR ratio similar to each other as a function of the Cu layer thickness. The phase of oscillation is much different from those in Co/Cu and fcc-FeCoNi/Cu MLs. The maximum MR ratios of 6% and 40% were obtained at 77 K, respectively, for (Fe 1.5 nm/Cu 1.4 nm)20 and (Fe56Co30N14 1.5 nm/Cu 1.4 nm)20 MLs. The EXAFS of the Cu K edge as well as the XRD pattern indicates that the structure of the Cu layers changes from bcc-like to fcc phase as their thickness increases. At the Cu thickness of 1.5 nm, the Cu layers, in both MLs, are highly disordered and seem to have a bct structure.

Perspective Chapter: Direct Energy Deposition of Cu-Fe System Functionally Graded Materials – Miscibility Aspects, Cracking Sources, and Methods of Assisted Manufacturing

“…The significant interest is attributed to the manufacturing of materials of the Cu-Fe system, which combine thermal expansion properties, electrical and thermal conductivity of bronze with high rigidity, mechanical strength (yield stress, ultimate tensile strength (UTS), flexure strength, creep resistivity), and corrosion resistance of stainless steel [19]. Moreover, the Cu-Fe alloys, especially multilayered, are characterized by significant values of magnetoresistance [20][21][22][23][24][25]. The applicability of different AM technologies for Cu-Fe FGMs fabrication was justified by the results of the following research: a.…”