Effect of exchange coupling on magnetic property in Sm–Co/ α -Fe layered system

Abstract

The hysteresis loops as well as the spin distributions of Sm-Co/α-Fe bilayers have been investigated by both threedimensional (3D) and one-dimensional (1D) micromagnetic calculations, focusing on the effect of the interface exchange coupling under various soft layer thicknesses t s . The exchange coupling coefficient A hs between the hard and soft layers varies from 1.8 × 10 −6 erg/cm to 0.45 × 10 −6 erg/cm, while the soft layer thickness increases from 2 nm to 10 nm. As the exchange coupling decreases, the squareness of the loop gradually deteriorates, both pinning and coercive fields rise up monotonically, and the nucleation field goes down. On the other hand, an increment of the soft layer thickness leads to a significant drop of the nucleation field, the deterioration of the hysteresis loop squareness, and an increase of the remanence. The simulated loops based on the 3D and 1D methods are consistent with each other and in good agreement with the measured loops for Sm-Co/α-Fe multilayers.

Micromagnetic simulations of reversal magnetization in cerium-containing magnets

“…When t = 5 nm, the coercivity reaches the largest value of 5.975 T. Then the coercivity decreases rapidly while t ranges from 5 nm to 8 nm. In theoretical reports on the hard/soft exchange spring system, [28][29][30][31][32] it has been found that when the thickness of the hard layer is larger than its domain wall width, the reversal magnetization process is not sensitive to the specific value of the hard layer. As for our work in this paper, it is assumed that the optimum shell thickness, t = 5 nm, might also be related to the domain wall width.…”

Interfacial effect on the reverse of magnetization and ultrafast demagnetization in Co/Ni bilayers with perpendicular magnetic anisotropy

“…The interfacial coupling constant also has an important influence in the SmCo/Fe and NdFeB/Fe exchange coupled systems, where the squareness of the hysteresis loop deteriorates with interfacial exchange coupling decreasing. [14][15][16]…”

Improvement of high-frequency properties of Co2FeSi Heusler films by ultrathin Ru underlayer*

“…where γ, H K , and 4πM S refer to the gyromagnetic ratio, magnetic anisotropy field, and saturation magnetization of the SMFs, respectively. There are many approaches to improve the zero-field FMR frequency, such as oblique sputtering, [4,10] composition gradient sputtering (CGS), [11] magnetoelectric coupling, [5,12] exchange coupling, [13][14][15] interlayer exchange coupled optical mode resonance, [16,17] in-serting a underlayer, [18][19][20][21] etc. Among them, the oblique deposition technique is a simple and easily controllable method to tailor the magnetic anisotropies in magnetic films.…”