Towards an alternative approach to achieve superconducting infinite-layer nickelate thin films

The recent discovery of superconductivity in the family of hole-doped infinite-layer nickelates (Nd_1-xSr_xNiO₂, x=dopant concentration) has given rise to an entirely new realm of research [1]. The superconducting phase is obtained after selectively removing all the apical oxygens from the perovskite phase by means of a complex chemical topotactic reduction using CaH₂ as a reducing agent [2]. This method prone to irreproducibility issues, which is hindering the development of the field. However, very recently, Wei et al. [3] reported superconductivity in Nd_0.75Eu_0.25NiO₂ infinite-layer phase by using an Al layer as an oxygen scavenger.

In this work, we will present the whole optimization process of Pr_0.80Sr_0.20NiO₃ thin films grown on STO (001) substrates to obtain the infinite-layer phase of nickelates by using Al sputtering deposition. In addition, we will discuss the key parameters for stabilizing the perovskite phase and the infinite-layer phase, comparing samples reduced by the two methods. Our findings could help in the development of a more reliable and reproducible method to attain superconducting infinite-layer samples.

References:

[1] D. Li et al., Nature 572 (2019) 624.

[2] K. Lee et al., APL Materials 8 (2020) 041107.

[3] W. Wei et al., Science Advances 9 (27) (2023) eadh3327.