Molecular spinterface in F4TCNQ-doped polymer spin valves

Abstract

The molecular spinterface is an ideal platform to realize multistate storage in organic spin valve (OSV) devices. However, as an effective strategy to enhance the conductivity and modify the spinterface, molecular doping has rarely been reported in vertical OSV devices, and the effect of artificial doping induced spinterface is not clear yet. Herein, we fabricated a F₄TCNQ-doped polymer spin valve with a stacking structure of La_2/3Sr_1/3MO₃ (LSMO)/poly(3-hexylthiophene-2,5-diyl) (P3HT)/tetrafluoro-tetracyanoquinodimethane (F₄TCNQ)/Co/Au, and found a significant improvement in conductivity and the magnetoresistance (MR) ratio. According to the characterization of interfacial states and investigation of half spin valves, it was determined that F₄TCNQ was doped in the form of free radicals and created a spin-dependent hybrid interfacial state (SDHIS). Such a SDHIS can exhibit an extra interface magnetoresistance (IMR) effect imposed on the standard giant magnetoresistance (GMR) effect. This interfacial doping strategy shows great potential for application in future multistate molecular spintronic devices and provides a new insight into the mechanism of radical-induced molecular spinterface.