Controlling spin-mixing conductance in KTaO3 2DEGs by varying argon-ion irradiation time

The Rashba-split two-dimensional electron gas (2DEG) at the surface and interface of insulating oxides such as KTaO3 (KTO) shows great promise for all-oxide spintronics. However, efficient spin current injection into the adjacent 2DEG remains a key challenge. In this study, we report the spin-pumping experiments on a 2DEG formed on the (001)KTO surface via Ar+ irradiation. We observed a significant increase in magnetic damping in the Ar+-KTO/Py bilayer compared to a non-irradiated KTO/Py control sample, confirming spin pumping into the 2DEG. We demonstrate that the spin-mixing conductance (g↑↓r) can be substantially enhanced by controlling the Ar+ irradiation time. The enhancement is attributed to increased 2DEG conductance, which results from a higher concentration of oxygen vacancies with longer irradiation times. This work provides crucial guidance for optimizing spin-to-charge conversion in KTO-based systems, highlighting the potential of Ar+-irradiated KTO 2DEGs for future oxide spintronics.