Resumen: Low dimensional carbon-based materials can show intrinsic magnetism associated to p-electrons in open-shell π-conjugated systems. Chemical design provides atomically precise control of the π-electron cloud, which makes them promising for nanoscale magnetic devices. However, direct verification of their spatially resolved spin-moment remains elusive. Here, we report the spin-polarization of chiral graphene nanoribbons (one-dimensional strips of graphene with alternating zig-zag and arm-chair boundaries), obtained by means of spin-polarized scanning tunnelling microscopy. We extract the energy-dependent spin-moment distribution of spatially extended edge states with π-orbital character, thus beyond localized magnetic moments at radical or defective carbon sites. Guided by mean-field Hubbard calculations, we demonstrate that electron correlations are responsible for the spin-splitting of the electronic structure. Our versatile platform utilizes a ferromagnetic substrate that stabilizes the organic magnetic moments against thermal and quantum fluctuations, while being fully compatible with on-surface synthesis of the rapidly growing class of nanographenes. Idioma: Inglés DOI: 10.1038/s41467-023-42436-7 Año: 2023 Publicado en: Nature communications 14, 6677 [8 pp.] (2023) ISSN: 2041-1723 Factor impacto JCR: 14.7 (2023) Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 8 / 134 = 0.06 (2023) - Q1 - T1 Factor impacto CITESCORE: 24.9 - Biochemistry, Genetics and Molecular Biology (all) (Q1) - Chemistry (all) (Q1) - Physics and Astronomy (all) (Q1)