Superconductivity in infinite-layer nickelates represents one of the major developments in condensed matter physics in recent years. Discovered in 2019, these materials are regarded as promising analogues of cuprate superconductors and provide a unique platform to deepen our understanding of unconventional superconductivity. However, their study has so far been limited by the significant complexity of their synthesis.

In a recent article published in Communications Materials, researchers from the Laboratoire Albert Fert report a simple and highly accessible synthesis method to obtain high-quality superconducting nickelate thin films. This approach relies on a topotactic reduction induced by aluminum deposition via magnetron sputtering, a widely used technique in thin-film deposition laboratories.

Specifically, a thin aluminum layer is deposited on a perovskite nickelate thin film (Pr₀.₈Sr₀.₂NiO₃). The aluminum acts as a reducing agent by selectively extracting oxygen atoms from the apical sites of the crystal lattice, thereby transforming the material into the superconducting infinite-layer phase (Pr₀.₈Sr₀.₂NiO₂). The deposition parameters were carefully optimized to achieve a complete and well-controlled transformation.

This method enables the fabrication of superconducting films with transition temperatures reaching up to 17 K, comparable to the state-of-the-art values reported for this compound. It also offers several key advantages over conventional chemical reduction techniques, such as those based on CaH₂, including improved reproducibility, enhanced control over structural disorder, and the possibility of performing the reduction entirely in situ, without air exposure.

Beyond the superconducting performance, the main strength of this approach lies in its experimental accessibility. By relying on a standard sputtering technique, it significantly lowers technical barriers and could enable a broader range of research groups to explore the physics of superconducting nickelates. This advance opens new perspectives for both fundamental studies and surface-sensitive characterizations of these materials.

This work was carried out in collaboration with the Laboratoire de Physique des Solides (LPS) and was supported by the French National Research Agency (ANR) through the JCJC OxyNicks project.

Reference

Accessible synthesis of superconducting nickelates via topotactic reduction induced by aluminum sputter deposition.

Dongxin Zhang, Aravind Raji, Luis M. Vicente-Arche, Alexandre Gloter, Manuel Bibes and Lucía Iglesias
Communications Materials 6, 293 (2025).

Link open access :  https://www.nature.com/articles/s43246-025-01013-9