Mobility of domain wall motion in the permalloy layer of a spin-valve-like trilayer

Abstract

et al.. Mobility of domain wall motion in the permalloy layer of a spin-valve-like Fe20Ni80/Cu/Co trilayer. Journal of Magnetism and Magnetic Materials, Elsevier, 2005, 293, pp. AbstractThe magnetization reversal of the magnetically soft permalloy (Fe 20 Ni 80 ) layer in a spin-valve like FeNi/Cu/Co trilayer was studied using photoelectron emission microscopy combined with x-ray magnetic circular dichroism, which allows to image the magnetic domain structure in an element-selective way. Nanosecond-short magnetic field pulses with amplitudes between 3.3 and 16.3 mT were applied one by one to reverse the magnetization of the FeNi layer. Images of the magnetic domain structure were taken after application of each pulse, and the mobility of magnetic domain wall motion in the FeNi layer was deduced. The reversal mechanism of the FeNi layer was found to depend on the applied pulse length, amplitude, and on the energy and direction of the coupling between the two ferromagnetic layers.

Magnetic domain wall creep in the presence of an effective interlayer coupling field

“…We demonstrate that creep theory can be used to describe the observed wall motion for fields jH þ H J j5H dep by including the resultant effective coupling field, H J , as a component of the total effective field which acts on the wall, as previously done for viscous domain wall motion [13]. In doing so, we determine a value for the effective coupling field (and subsequently the interlayer coupling energy), consistent with that measured from the shift of the soft layer's minor hysteresis loop obtained using optical magnetometry.…”

“…(2)) to include the effective coupling field, H J , as a component of the total effective field acting on the wall (as done for viscous domain wall motion [13]):…”

“…Since domain wall motion is often the dominant reversal mechanism in these mutlilayer devices [2,3], it is important to understand how it is altered in such systems due, for example, to coupling between the multiple layers. However, while the dynamics of domain walls in continuous [4][5][6][7][8] and patterned [9][10][11][12] single layer films are rather well understood, the extent of quantitative measurements of domain wall dynamics in bilayer and multilayer magnetic systems remains quite limited [13][14][15][16], especially in systems with perpendicular anisotropy.…”

Experimental study of spin-wave dispersion in Py/Pt film structures in the presence of an interface Dzyaloshinskii-Moriya interaction

“…(See, for example, Ref. [36], dedicated to the study of the mobility of domain wall motion, where the reported value is 1.79×10 11 T −1 s −1 .) At the same time, in a recent paper [37] addressing precise determination of the spectroscopic g factor in Permalloy by broadband ferromagnetic resonance measurements, the following value has been reported: 2.109 ± 0.003.…”

Asymmetry of the magnetization reversal process in a magnetic tunnel junction

“…Only few results were reported so far on reversal asymmetry in a soft magnetic layer coupled to a harder one by dipolar interaction. 8,9 In this paper, we show that an asymmetry in the magnetization reversal can occur in spite of an apparently symmetric shape of the macroscopic hysteresis loop. Indeed, magnetic relaxation measurements are used to analyze the magnetization reversal of a magnetic tunnel junction's ͑MTJ͒ dipolar coupled soft layer.…”