Strain‐Induced Giant Enhancement of Magnetism in RuO ₂ Films

ABSTRACT RuO 2 has garnered significant attention as a promising candidate for next‐generation spintronic devices due to its intriguing magnetic properties. However, its intrinsic magnetic behavior remains a subject of intense debate. Here, we demonstrate a remarkable enhancement of magnetism in RuO 2 films via strain engineering through substrate selection. Specifically, under identical conditions, the magnetic response of RuO 2 (110) thin films grown on (110)‐TiO 2 substrates is more than 40 times greater than that of RuO 2 films with the (110) orientation grown on (100)‐MgO substrates. High‐resolution electron microscopy and X‐ray photoelectron spectroscopy analysis confirmed that this enhancement is attributed to strain‐induced oxygen vacancies. These findings underscore the critical role of substrate‐induced strain and defect engineering in modulating the magnetic properties of RuO 2 . This work provides fundamental insights into the intricate interplay among growth dynamics, strain effects, and magnetism in RuO 2 , paving the way for future investigations into its spintronic applications.