Enhanced superconductivity and mixed-dimensional behaviour in infinite-layer samarium nickelate thin films.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41690958.
- Also identified by DOI 10.1038/s41467-026-69650-3 and PMC identifier 13018478.
- Licence recorded as CC BY-NC-ND.
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Abstract
Rare-earth infinite-layer nickelates are emerging unconventional superconductors, with materials synthesis largely limited to early lanthanide compounds. Here, we report phase-pure samarium-based nickelate thin films on (LaAlO<sub>3</sub>)<sub>0.3</sub>(Sr<sub>2</sub>TaAlO<sub>6</sub>)<sub>0.7</sub> (001) substrates, including the first demonstration of Sm<sub>1-x</sub>Sr<sub>x</sub>NiO<sub>2</sub>. Co-doped compounds achieve a record-small c-axis parameter (3.26 Å) and superconducting transitions up to 32.5 K, revealing a clear correlation between decreasing c-axis parameter and increasing critical temperature across different rare-earth systems. Angle-dependent magnetoresistance shows a hybrid 2D/3D superconductivity with enhanced rare-earth 5d-Ni 3 d orbital coupling, confirmed by resonant inelastic X-ray scattering. In addition, increasing Eu concentration drives a shift toward 3D superconductivity, and Eu-containing samples exhibit distinctive negative magnetoresistance even in the superconducting state. These findings advocate clear materials design principles for higher transition temperatures and exotic physics in infinite-layer nickelate superconductors through structural engineering of the rare-earth site.