Magnetic ordering of Cr layers on Fe(100)

Abstract

The magnetic ordering at the surface of epitaxial Cr overlayers on Fed 00) is studied by spinpolarized electron-energy-loss spectroscopy. The exchange asymmetry oscillates with the thickness of the Cr overlayer with a period of about two atomic layers, proving directly that the surface Cr layer has a net ferromagnetic moment and that successive layers order antiferromagnetically. The exchange asymmetry is predominantly due to spin-flip scattering. The spin-flip spectrum broadens toward lower energy with increasing thickness, suggesting that Cr may have a surface-enhanced magnetic moment.

Topmost layer magnetization of ultrathin Cr films on Fe(100) from proton-induced spin-polarized electron emission

“…An antiferromagnetic stacking of layers, as expected for Cr/Fe͑100͒, thus causes a gradual decrease of the measured polarization with increasing coverage, in agreement with our observation and previous studies on electron-induced electron emission. 3,14 Nevertheless, we do not observe a layer-by-layer change in sign for proton impact, in agreement with the highly surface sensitive experiments of Walker et al 10 The layer-dependent magnetic moments can be estimated by fitting the data for proton excitation from Fig. 2͑a͒, assuming a proportionality between spin polarization and magnetization,…”

“…3 Although a number of experimental techniques, mainly based on spin-and, in some cases, energy-resolved scattering of electrons, have been applied, the magnetic behavior of the first few layers remained unclear. Walker et al 10 infer from slightly negative asymmetries in spin-polarized electronenergy-loss spectroscopy that 1 ML Cr grown at 470 K couples antiferromagnetically to Fe, in agreement with results from magnetically sensitive core level spectroscopies. [11][12][13] Upon further deposition, the asymmetry maintains the same sign as for clean Fe up to coverages of about 8 ML.…”

Photoemission study of the spin-density-wave state in thin films of Cr

“…7 One of the mostly investigated systems Fe/ Cr/ Fe͑100͒ shows that the ferromagnetic or AF type of coupling between Fe layers varies with thickness of Cr spacer following the short period, whereas the strength of the coupling changes with the long period of oscillations. [8][9][10][11] The description of the SDW in thin films is complicated by the fact that the boundary conditions at the interfaces have to be properly considered. In the density-functional theory (DFT) study of Fe/ Cr/ Fe͑100͒ by Niklasson et al 12 mainly AF order was found for Cr spacers with thicknesses Ͻ10 ML.…”

Spin polarization and exchange coupling of Cu and Mn atoms in paramagnetic CuMn diluted alloys induced by a Co layer

“…This is experimentally challenging given that the polarization may be small, located at a buried interface and in proximity to material with a much larger magnetization. Nonetheless, experimentally determining the spatial polarization has widespread significance in areas such as Ruderman-Kittel-Kasuya-Yoshida ͑RKKY͒ interlayer coupling, [6][7][8] induced proximity magnetism 9 and in the case of spin injection, the driven accumulation 10,11 of spin at an interface. Understanding the mechanisms behind the equilibrium and out-of-equilibrium magnetization becomes important to the future realization and technological exploitation of spin-electronic devices, in particular, the lengthscale over which the spin functionality can be transported.…”