Giant Spin Pumping at Polymer/Ferromagnet Interfaces for Hybrid Spintronic Devices

Journal article, 2025

While the growing utilization of polymers in flexible electronic devices has sparked significant interest in polymer/metal interfaces, spintronic studies of such interfaces remain limited. Here, spin pumping across a polymer/ferromagnet metal interface is systematically studied between hydrogen silsesquioxane (HSQ) oligomer layers (t(HSQ) = 30, 36, 48 nm) and NiFe (t(NiFe) = 4, 5, 7, 10 nm) thin films. Using ferromagnetic resonance measurements, strong spin pumping (large linewidth broadening) and a giant spin mixing conductance, reaching 19.8 nm(-2) for HSQ = 48 nm are observed, i.e. comparable to that of heavy metals. The results suggest efficient spin transfer across the HSQ/NiFe interface, possibly originating from a combination of spin and orbital pumping, and provide valuable insights for designing self-powered and flexible spintronic devices utilizing polymers in combination with ferromagnetic materials.