Magnetic properties and domain structure studies in dc triode-sputtered permalloy/carbon multilayer films

Abstract

Double-layer and multiple-layer thin films of permalloy with carbon as a intermediate nonmagnetic spacer were prepared by low-energy dc triode sputtering. Coupling between the two layers of the double films is investigated on a series of samples with a fixed thickness of permalloy layers (dp = 300 Å) and thickness of the carbon layer dc, varying from 0 to 25 Å. Thickness dc = 10 Å is found to be the limiting value for the carbon layer to be continuous and 20 Å for domain structures in the two magnetic films to decouple. Saturation magnetization Ms, uniaxial anisotropy field, Hk, and coercive force Hc of multilayers with dc = 10 Å and dp from 50 to 600 Å (number of magnetic layers from 12 down to 1) are measured and found consistent with earlier results by other authors. Multiple domain walls in the multilayers are investigated by Lorentz electron microscopy.

Micromagnetism and magnetization reversal of embedded ferromagnetic elements

“…Each quasiwall is either located on top or below a corresponding Néel wall and acts as a means to compensate the stray field of that wall, making this configuration energetically favorable. Twin walls of this type could indeed be detected experimentally, [21][22][23][24][25] and, in addition, evidence was found that a Néel wall and its adjacent-lying quasi-Néel wall companion can intercross each other. 21 Both Fig.…”

“…5 that a domain wall must form at the boundary between irradiated and nonirradiated areas, but the exact nature of this domain wall remains a priori unclear. However, previous works [17][18][19][20][21][22][23][24][25][26] devoted to the nature of domain walls in magnetic trilayers provide some insight into what might be expected from a theoretical point of view. Within the scope of these works, trilayers of the form NiFe/ X / NiFe were investigated, where X represents a nonmagnetic interlayer material like C or SiO and both NiFe layers have the same thickness.…”

Electron microscopy studies of spin-valve materials

“…The reason for this is that the images were recorded at a temperature of 250 • C, which is much higher than the blocking temperature of MnFe, and as a result the exchange coupling between the pinned and the pinning layers has disappeared. The reversal process of the two layers thus occurs together, initially via magnetization rotation, followed by the nucleation of double domain walls, as observed by Gupta et al [86] for NiFe layers coupled across a C-spacer layer. These consist of two walls, one in each of the two FM layers and can be seen in figure 14(c) for an applied field value of 10 Oe.…”

Effect of non-magnetic intermediate layer on film structure, magnetic properties, and noise characteristics of FeCSi soft magnetic multilayers

“…3(a), the coercive force of the multilayer with C layers was smaller than that of the monolayer. Previous papers [6,7] have reported that the coercive force of a soft magnetic multilayer with amorphous C or Si intermediate layers is smaller than that of a soft magnetic monolayer. Our results are consistent with these reports.…”