Spinterface Formation at α-Sexithiophene/Ferromagnetic Conducting Oxide

The inorganic/molecular spinterface is an ideal platform for generating extraordinary spin effects. Understanding and controlling these spin-related effects is mandatory for the exploitation of such interfaces in devices. For this purpose we have investigated the adsorption of α-sexithiophene (α-6T) on La0.7Sr0.3MnO3 (LSMO) as one of the prototypical material combinations used in organic spintronic devices. Atomic force microscopy (AFM), confocal photoluminescence, X-ray and utraviolet photoelectron spectroscopy, and metastable de-excitation spectroscopy unraveled the structure and the electronic configuration of 6T for various surface coverages. This data set allowed the determination of the characteristic features of occupied states: the band diagram and the work function. Finally, density functional theory enabled us to establish that the spin polarization in 6T molecular orbitals critically depends on the termination layer of LSMO, showing a substantial effect on the MnO-terminated one only. We believe that this research provides important hints for a comprehensive understanding of spinterface effects in general and offers key suggestions for the optimization of 6T/LSMO-based spin devices through the engineering of LSMO termination layer.