We investigate the possibility of obtaining an infinite-layered superconducting nickel oxide using a topotactic reduction of $R_{2-x}{\mathrm{Sr}}_x{\mathrm{NiO}}_4$ nickelate compounds. We consider the case of reducing ${\mathrm{La}}_{0.8}{\mathrm{Sr}}_{1.2}{\mathrm{NiO}}_4$, which is metallic and with an effective ${\mathrm{Ni}}^{3.2+}$ valence into ${\mathrm{La}}_{0.8}{\mathrm{Sr}}_{1.2}{\mathrm{NiO}}_3$ with an effective ${\mathrm{Ni}}^{1.2+}$ valence similar to the original superconducting nickelate. Here we show that the reduction process is more likely to produce a ${\mathrm{NiO}}_2$ square striped structure instead of a layered structure, yielding an insulating state associated to a charge-ordered pattern of ${\mathrm{Ni}}^{+}$ and ${\mathrm{Ni}}^{2+}$ cations and antiferromagnetism. Although the appropriate valence for Ni cations is reached, it appears that both the crystal structure and the dimensionality of the system are critical for reaching superconductivity in these nickelates.

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• Doping effects
• 1-dimensional spin chains
• Antiferromagnets
• Magnetic insulators
• Mott insulators
• Nickelates
• Rare-earth magnetic materials
• Superconductivity
• Density functional theory