Controlling Spin-Mixing Conductance in KTaO$_{3}$ 2DEGs by Varying Argon-Ion Irradiation Time

TL;DR

This paper demonstrates that varying argon-ion irradiation time on KTaO$_{3}$ surfaces can effectively control the spin-mixing conductance of 2DEGs, enhancing spin injection efficiency for oxide spintronics applications.

Contribution

It introduces a method to tune spin-mixing conductance in KTaO$_{3}$ 2DEGs by controlling Ar$^+$ irradiation time, linking it to oxygen vacancy concentration.

Findings

Spin pumping confirms efficient spin injection into irradiated 2DEGs.

Spin-mixing conductance increases with longer irradiation times.

Enhanced conductance correlates with higher oxygen vacancy concentration.

Abstract

The Rashba-split two-dimensional electron gas (2DEG) at the surface and interface of insulating oxides like KTaO$_{3}$ (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 ($g_{\uparrow\downarrow}^r$) 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.