Interlayer segregation in magnetic multilayers and its influence on exchange coupling

Abstract

Experimental results show that the exchange coupling field (Hex) of NiFe/FeMn for Ta/NiFe/FeMn/Ta multilayers is higher than that for spin-valve multilayers Ta/NiFe/Cu/NiFe/FeMn/Ta. X-ray photoelectron spectroscopy shows that Cu atoms segregate to the NiFe/FeMn interface for Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers. While studying Ta/X(X=Bi,Pb,Ag,In)/NiFe/FeMn multilayers, we also find that X atoms segregate to the NiFe/FeMn interface, which results in a decrease of the Hex. However, a small amount of Bi, Pb, etc. deposited between Cu and pinned NiFe layer for Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers can increase Hex.

Monotonically Decreasing Ferromagnetic Resonance Linewidth of Cu/Ni0.81Fe0.19 Bilayer Heterostructures with the Increasing Sputtering Rate of the Cu Layer

“…There would be two reasons for the small M S of Cu/NiFe samples, with the bulk NiFe’s M S 0 of 7.9 × 10 5 A/m (790 emu/cc) . First, due to Cu’s smaller surface free energy compared with NiFe, Cu atoms can be in the NiFe layer during the deposition process to decrease the total surface and interface energy . Second, the reduced magnetization of Cu/NiFe films was reported due to the effects at interfaces .…”

Improving exchange-coupling field in the same thickness of pinned magnetic layer

“…It has been known for more than 50 years [1,2] and extensively studied by both experiments and theoretical analysis [3][4][5][6][7][8][9][10][11][12]. However, its physical mechanism remains unappreciated.…”

Study on NiO/Fe interface with X-ray photoelectron spectroscopy

“…Most theoretical models presume an ideal interface between FM and AFM. However, many reports indicate that magnetic properties are sensitive to the roughness, atomic diffusion, chemical status, and the geometrical structure of the interfaces [8][9][10][11][12][13][14]. In view of its applications, the properties of small-scale devices rely on the quality and thickness of the interfaces.…”