Evaluating the magnetic momentum accumulation in early 3d transition metal oxides by X-ray Absorption Spectroscopy

An important mechanism in spintronics is the Spin Hall effect (SHE), where a charge current (JC) in a nonmagnetic material with spin orbit coupling (SOC) generates spin angular momentum (JS) and spin accumulation at sample surfaces. While initially observed optically, spin accumulation has been also directly visualized using X-ray magnetic circular dichroism (XMCD) in PEEM experiments. It's increasingly acknowledged that spin currents stem from an induced orbital current, particularly prevalent in early transition metals. Recent experiments at BOREAS bl aimed to explore orbital momentum accumulation in SrVO3 (SVO) under AC charge currents using Partial Electron Yield (PEY) detection. Promising results were obtained but further investigations are needed to validate the observed signal's nature. With the present proposal, our objective is to demonstrate a new method to probe angular momentum accumulation and deduce its orbital nature combining XMCD in PEY configuration and AC currents in patterned early transition metal oxides (e.g., SVO) and metallic layers (i.e., Ti, Cr, Pt). Previous studies using x-rays and magneto-optics have detected spin accumulation in Cu/Co bilayers, Pt, W single layers, and recently in Cu1-xBix at the CIRCE beamline, but none have addressed early 3d metals or attempted to differentiate between orbital and spin currents. Additionally, from the BOREAS beamline standpoint, this experiment is viewed as the final stage of the ongoing commissioning process of a new 500 MHz synchronous PEY detection, from which all users will be able to benefit soon.