Unveiling the role of Fe3O4 in polymer spin valve near Verwey transition
polymer spin valves, Fe3O4, Verwey transition, magnetoresistance
The spinterface formed between ferromagnetic (FM) electrode and organic materials is vital for performance optimization in organic spin valve (OSV). Half-metallic Fe3O4 with drastic change in structure, conductivity and magnetic property near Verwey transition can serve as an intrinsic spinterface regulator. However, such modulating effect of Fe3O4 in OSV has not been comprehensively investigated, especially below the Verwey transition temperature (Tv). Here, we highlight the important role of Fe3O4 electrode in reliable-working and controllable Fe3O4/P3HT/Co polymer spin valves by investigating the magnetoresistance (MR) above and below Tv. In order to distinguish between different contributions to charge transport and related MR responses, the systematic electronic and magnetic characterizations were carried out in full temperature range. Particularly, the first-order metal-insulator transition in Fe3O4 has a dramatic effect on the MR enhancement of polymer spin valves at Tv. Moreover, both the conducting mode transformation and MR line shape modulation could be accomplished across Tv. This research renders unique scenario to multimodal storage by external thermodynamic parameters, and further reveals the importance of spin-dependent interfacial modification in polymer spin valves.
Tsinghua University Press
Shuaishuai Ding, Yuan Tian, Xiang Liu, Ye Zou, Huanli Dong, Wenbo Mi, Wenping Hu. Unveiling the role of Fe3O4 in polymer spin valve near Verwey transition. Nano Research 2021, 14(1): 304-310.