Figure 1

(a) SPEEL spectra measured on a 2 ML Fe film epitaxially grown on W(110). The incoming electron beam had an energy of $E_0=4\mathrm{eV}$. The inset shows the geometry of our SPEELS experiment. The spin-polarized electron beam is scattered along the [001] direction of the Fe(110) surface in the magnetic remanent state. The scattering angle is kept at ${\theta }_0=80°$. By changing the incident angle $\theta$, the in-plane wave-vector transfer parallel to the surface, $\Delta K^{\parallel }$, can be adjusted [$\Delta K^{\parallel }=k_f\sin ({\theta }_0-\theta )-k_i\sin (\theta )$, where $k_i$ and $k_f$ are the initial and final momentums of the electrons, respectively]. For this experiment it was chosen to be $\Delta K^{\parallel }=0.5{\AA }^{-1}$. (b) The difference and asymmetry spectra. The big triangles show the peak position due to the SW creation and annihilation taking place in energy loss and gain, respectively.Reuse & Permissions

Figure 2

(a) Series of difference, $\mathrm{diff}=I_{\downarrow }-I_{\uparrow }$, and (b) asymmetry, $\mathrm{asy}=\frac{I_{\downarrow }-I_{\uparrow }}{I_{\downarrow }+I_{\uparrow }}$, SPEEL spectra measured for $\Delta K^{\parallel }=\pm 0.5{\AA }^{-1}$ on a 2 ML Fe at RT. The filled symbols are for $\mathbf{M}\parallel [\overline{1}10]$ and the open ones are for $\mathbf{M}\parallel [1\overline{1}0]$. The spectra are recorded at a beam energy of $E_0=4.163\mathrm{eV}$ with an energy resolution of 19 meV. The big triangles mark the peak positions of SW creations and annihilations, taking place at energy loss and gain, respectively.Reuse & Permissions

Figure 3

(a) The energy asymmetry as a function of wave-vector transfer. The symbols are the measured values for two different magnetization directions and the solid curves are the fits using Eq. (2) for $c=+1$ and different magnetization directions. The error bars represent both the statistical and systematic uncertainties. (b) Real space representation of a 2 ML Fe slab.Reuse & Permissions