Influence of organic/ferromagnetic interfacial resistance upon spin-transport in Co/PVDF/Fe3O4 organic ferroelectric spin valves

Abstract

This article investigates room-temperature spin transport in organic ferroelectric spin valve devices, separated by polyvinylidene fluoride (PVDF) thin films. The impedance mismatch at the ferromagnetic/organic semiconductor (OSC) interface poses a significant challenge to efficient electrical spin injection into OSCs. To address this, different resistive Fe3O4 electrodes with varied work functions have been employed as spin injectors. Our study shows that a resistive Fe3O4 spin-injecting electrode can enhance spin injection efficiency by reducing the impedance mismatch. In this work, we recorded a maximum room-temperature magnetoresistance (MR) of (3.76 ± 0.96)%, which is the highest MR value reported to date in PVDF-based spin valves. Furthermore, the presence of significant MR in the thicker PVDF spacer layer up to 230 nm thickness suggests a large spin-diffusion length and their potential for room-temperature organic spintronic devices.