High-Resolution X-Ray Studies of the Direct Spin Contact of EuO with Silicon

Ferromagnetic semiconductor europium monoxide (EuO) is believed to be an effective spin injector when directly integrated with silicon. Injection through spin-selective ohmic contact requires superb structural quality of the interface EuO/Si. Recent breakthrough in manufacturing free-of-buffer-layer EuO/Si junctions calls for structural studies of the interface between the semiconductors. Ex situ high-resolution X-ray diffraction and reflectivity accompanied by in situ reflection high-energy electron diffraction reveal direct coupling at the interface. A combined analysis of XRD and XRR data provides a common structural model. The structural quality of the EuO/Si spin contact by far exceeds that of previous reports and thus makes a step forward to the ultimate goals of spintronics.