Tuning spin-orbit coupling strength with electrolyte gating of IrO₂ thin films

5d-transition metal oxides (TMO) have gained much interest due to the delicate interplay of charge, lattice, spin, and orbital degrees of freedom in these materials and their potential applications in spintronics. Here, we demonstrate the electrolyte gating of high-quality IrO₂ thin films grown by solid-source metal-organic molecular beam epitaxy (SSMOMBE) using ion gels. Low-temperature magneto-transport measurements at different gate voltages show weak anti-localization behaviors due to spin-orbit interactions. Fitting with theoretical models reveals the spin relaxation mechanism is spin splitting in these films and the spin relaxation length can be tuned by applying gate voltage. A detailed temperature- and gate-voltage-dependent transport study combined with theoretical models will be presented. The electrostatic and electrochemical nature of the electrolyte gating of IrO₂ thin films will also be discussed. This work will provide insights into future manipulation of a variety of functionalities in 5d-transition metal oxides.