Although spintronics has demonstrated potential for high-density, low-power electronic devices, performance often falls short of theoretical predictions owing to challenges in efficient spin injection and transport. Prior research has highlighted the role of molecular design in modulating interfacial properties; nonetheless, the impact of different anchoring atoms on spin relaxation, particularly during tunneling transport, remains largely unexplored. We fabricated Fe3O4/molecule hybrid nanoparticles through self-assembly to investigate experimentally and theoretically how different anchoring atoms — S and C (−COOH, −SO3H, −OSO3H) — affect the electrical and magneto-transport properties at the Fe3O4/molecule interface, as well as intramolecular spin relaxation and the associated physical mechanisms. Electrical transport measurements revealed that the contact resistivity at the Fe3O4/molecule interface was highly sensitive to the anchoring groups, in marked contrast to the tunnel attenuation coefficient β. Meanwhile, magneto-transport results demonstrated that replacing the carbon-centered anchoring group (−COOH) with sulfur-centered groups (−SO3H, −OSO3H) reduced the magnetoresistance and shortened the intramolecular spin diffusion length by ~69% compared with the carbon-centered anchoring group (−COOH). The theoretical studies clarified the role of orbital hybridization in tuning interfacial spin properties. We also examined the influence of magnetic field and temperature on intramolecular spin relaxation during tunneling and discussed the underlying mechanisms. This study experimentally verified, for the first time, the occurrence of spin relaxation within organic molecules during tunneling.
Shi et al. (Thu,) studied this question.