Enhancement of spin diffusion length in tunneling junctions by benzene ring insertion into the saturated alkyl sulfonic acid

Abstract

We fabricated Fe3O4/alkyl-sulfonic acid and Fe3O4/alkyl-benzene sulfonic molecules hybrid nanoparticles using self-assembled monolayers to investigate the impact of benzene ring insertion on the spin tunneling through molecules. The results showed that benzene ring insertion decreased the tunnel barrier height, slightly tuned the magnetoresistance values, and enhanced the intramolecular spin diffusion length by ∼1.5 times. We proposed an extended model to explore the interfacial magnetic properties. The fitting results indicated that benzene ring insertion changed the magnetic properties of the shell layer. This work first demonstrated that benzene ring insertion enhanced the intramolecular spin diffusion length during the tunneling process.