Limits to the strain engineering of layered square-planar nickelate thin films.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36928184.
- Also identified by DOI 10.1038/s41467-023-37117-4 and PMC identifier 10020545.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The layered square-planar nickelates, Nd<sub>n+1</sub>Ni<sub>n</sub>O<sub>2n+2</sub>, are an appealing system to tune the electronic properties of square-planar nickelates via dimensionality; indeed, superconductivity was recently observed in Nd<sub>6</sub>Ni<sub>5</sub>O<sub>12</sub> thin films. Here, we investigate the role of epitaxial strain in the competing requirements for the synthesis of the n = 3 Ruddlesden-Popper compound, Nd<sub>4</sub>Ni<sub>3</sub>O<sub>10</sub>, and subsequent reduction to the square-planar phase, Nd<sub>4</sub>Ni<sub>3</sub>O<sub>8</sub>. We synthesize our highest quality Nd<sub>4</sub>Ni<sub>3</sub>O<sub>10</sub> films under compressive strain on LaAlO<sub>3</sub> (001), while Nd<sub>4</sub>Ni<sub>3</sub>O<sub>10</sub> on NdGaO<sub>3</sub> (110) exhibits tensile strain-induced rock salt faults but retains bulk-like transport properties. A high density of extended defects forms in Nd<sub>4</sub>Ni<sub>3</sub>O<sub>10</sub> on SrTiO<sub>3</sub> (001). Films reduced on LaAlO<sub>3</sub> become insulating and form compressive strain-induced c-axis canting defects, while Nd<sub>4</sub>Ni<sub>3</sub>O<sub>8</sub> films on NdGaO<sub>3</sub> are metallic. This work provides a pathway to the synthesis of Nd<sub>n+1</sub>Ni<sub>n</sub>O<sub>2n+2</sub> thin films and sets limits on the ability to strain engineer these compounds via epitaxy.