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, we systematically study spin pumping across a polymer/ferromagnet metal interface between hydrogen silsesquioxane (HSQ) oligomer layers (tHSQ=30,36,48 nm) and NiFe (tNiFe=4,5,7,10 nm) thin films. Using ferromagnetic resonance measurements, we observe strong spin pumping (large linewidth broadening) and a giant spin mixing conductance, reaching 19.8~nm−2 for HSQ = 48 nm, \emph{i.e.}~comparable to that of heavy metals. Our 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.
@article{arxiv.2503.22623,
title = {Giant Spin Pumping at Polymer/Ferromagnet Interfaces for Hybrid Spintronic Devices},
author = {Shiva Gaur and Akash Kumar and Himanshu Bangar and Utkarsh Shashank and Hukum Singh and Saroj P. Dash and Anubhav Raghav and Johan Åkerman},
journal= {arXiv preprint arXiv:2503.22623},
year = {2025}
}