Fig. 4

Angle dependent XMCD-PE\(_{\text {meas}}\) of the Eu 3d\(_{5/2}\) and Co (Fe) 2p core levels obtained from \(3\) nm thin EuO films capped with \(4\) nm of Co, (a), (c), and Fe, (b), (d) at \(T_{\text {low}}\), (a), (b), and \(T_{\text {high}}\), (c), (d). The dashed line in (a) is the reference signal of a bare \(3\) nm thin film of EuO in NE (\(\Theta =3\)°). Note that for the sake of visibility the scaling of the y-axes varies. The grayish area serves as a guide to the eye, indicating the XMCD-PE\(_{\text {meas}}\) range from \(-3\) to \(+3\). For all samples, angles and temperature, a non-zero XMCD-PE\(_{\text {meas}}\) of Eu is observed. Obviously, interfacing a thin EuO film with Co or Fe switches the magnetization direction with respect to the bare EuO film. At \(T_{\text {low}}\) the XMCD-PE\(_{\text {meas}}\) of Eu is larger for the film interfaced with Co than with Fe. The amplitudes of all XMCD-PE\(_{\text {meas}}\) decrease with increasing \(\Theta\).