Cu metal / Mn phthalocyanine organic spinterfaces atop Co with high spin polarization at room temperature

TL;DR

This study demonstrates a highly spin-polarized Cu/MnPc organic spinterface on Co at room temperature, showing robustness and potential for integrating fragile molecules and manipulating molecular spins.

Contribution

It reveals a robust, highly spin-polarized organic spinterface with Cu spacer layers on Co, combining experimental and theoretical insights into its magnetic properties.

Findings

Spin polarization persists up to 10 monolayers of Cu.

The spinterface exhibits magnetic hardening effects.

The system enables manipulation of molecular spins via spin transfer torque.

Abstract

The organic spinterface describes the spin-polarized properties that develop, due to charge transfer, at the interface between a ferromagnetic metal (FM) and the molecules of an organic semiconductor. Yet, if the latter is also magnetic (e.g. molecular spin chains), the interfacial magnetic coupling can generate complexity within magnetotransport experiments. Also, assembling this interface may degrade the properties of its constituents (e.g. spin crossover or non-sublimable molecules). To circumvent these issues, one can separate the molecular and FM films using a less reactive nonmagnetic metal (NM). Spin-resolved photoemission spectroscopy measurements on the prototypical system Co(001)//Cu/Mnphthalocyanine (MnPc) reveal that the Cu/MnPc spinterface atop ferromagnetic Co is highly spin-polarized at room temperature, up to Cu spacer thicknesses of at least 10 monolayers. Ab-initio theory describes a spin polarization of the topmost Cu layer after molecular hybridization that can be accompanied by magnetic hardening effects. This spinterface's unexpected robustness paves the way for 1) integrating electronically fragile molecules within organic spinterfaces, and 2) manipulating molecular spin chains using the well-documented spin transfer torque properties of the FM/NM bilayer.