Spin-transport across PVDF-HFP thin films in Ag/(Co, NiFe)/PVDF-HFP/Fe3O4 organic spin valves

This article investigates the potential of polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) thin films as a spin-transport medium. Our study addresses various aspects of PVDF-HFP spacer-based organic spin valve (OSV) operation by focusing on spin transport efficiency study with respect to different ferromagnetic (FM) electrodes, spacer thickness, and electrical poling. By introducing Fe3O4 as the spin-injecting bottom electrode, significant enhancement in spin transport has been achieved at room temperature. The interfaces between (Co, NiFe) and PVDF-HFP are found to play a critical role in improving the measured magnetoresistance (MR). A maximum MR of (0.92 +/- 0.09)% is experimentally observed in an OSV with an 80 nm thick semi-crystalline PVDF-HFP spacer. Furthermore, the impact of electrical poling on spin transport has been examined by evaluating MR variations under different poling fields. The robust bi-stable resistance switching, even with 160 nm thick PVDF-HFP spacer, indicates a high spin scattering length, emphasizing its relevance for future spintronic applications.