Yilmaz, HasanKüster, KathrinStarke, UlrichClemens, OliverIsobe, MasahikoPuphal, Pascal2025-07-1620242397-4648http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-ds-168120https://elib.uni-stuttgart.de/handle/11682/16812https://doi.org/10.18419/opus-16793The discovery of 80 K superconductivity in bilayer La3Ni2O7 at pressures greater than 14 GPa presents a unique opportunity to study a novel class of high-temperature superconductors. Therefore, other bilayer nickelates following the classical (T4+) Ruddlesden-Popper (RP) series of Sr3Ni2O7 would present an interesting new candidate. In this work, we study the stabilization of RP n = 2 phase in Sr3Ni2-xAlxO7-δ, via floating zone growth of crystals. With powder and single-crystal XRD, we study the stability range of the RP-type phase. Our Thermogravimetric Analysis (TGA), X-ray photoelectron spectroscopy (XPS) and gas extraction studies reveal a remarkably high oxidation state of Ni4+ stabilized by chemical strain from Al. The obtained black crystals are insulating in transport and show a magnetic transition around 12 K.enCC BYinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by/4.0/660article2025-01-27