Spin currents have long been suggested as a potential solution to addressing circuit miniaturization challenges in the semiconductor industry. While many semiconducting materials have been extensively explored for spintronic applications, issues regarding device performance, materials stability, and efficient spin current generation at room temperature persist. Nonconjugated paramagnetic radical polymers offer a unique solution to these challenges. Despite the recent observation of organic magnetism and magnetoresistance phenomena in radical polymers, their spin propagation properties have not been thoroughly studied. Here, we show that a nonconjugated radical polymer is an exceptional spin transport medium. It shows large effective spin mixing conductance of 3.2 × 1019 m-2 and a room temperature spin diffusion length of 105 nm. Its temperature-independent spin diffusion length suggests that exchange-mediated transport governs spin transport. The substantial spin mixing conductance is promising, and these results establish the potential of radical polymers in emerging spin-based applications.
© 2025. The Author(s).