Superconducting Nd<sub>1-<i>x</i></sub>Eu<i><sub>x</sub></i>NiO<sub>2</sub> thin films using in situ synthesis.

Wei, Wenzheng; Vu, Dung; Zhang, Zhan; Walker, Frederick J; Ahn, Charles H · Sci Adv · 2023

basic_science · Level V

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Abstract

We report on superconductivity in Nd<sub>1-<i>x</i></sub>Eu<i><sub>x</sub></i>NiO<sub>2</sub> using Eu as a 4f dopant of the parent NdNiO<sub>2</sub> infinite-layer compound. We use an all-in situ molecular beam epitaxy reduction process to achieve the superconducting phase, providing an alternate method to the ex situ CaH<sub>2</sub> reduction process to induce superconductivity in the infinite-layer nickelates. The Nd<sub>1-<i>x</i></sub>Eu<i><sub>x</sub></i>NiO<sub>2</sub> samples exhibit a step-terrace structure on their surfaces, have a <i>T</i><sub>c</sub> onset of 21 K at <i>x</i> = 0.25, and have a large upper critical field that may be related to Eu 4f doping.