Targeted modification of interfacial structure in epitaxially-strained rare-earth nickelate heterostructure
Physical Chemistry of Solids and Surfaces, Material Characterisation
Final Report Abstract
The aim of the project was to study the manipulation possibilities of the LaNiO3 structure and electrical properties through heterostructuring. We systematically investigated LaNiO3-LaGaO3 superlattices to understand the importance of the relative layer thickness ratio of the superlattice components. The superlattices were synthesized by pulsed-laser deposition onto a SrTiO3 substrate. While the substrate provided the same heteroepitaxial strain to the superlattices, the ratio of the LaNiO3 and LaGaO3 components was varied. Dedicated and optimized TEM samples were prepared by FIB. For AC-HRTEM experiments, negative Cs imaging condition were applied to obtain HRTEM images of oxygen atomic columns and identify the octahedral behavior of the components. Accompanying spectroscopic analysis (EDX), image simulation, and quantitative analysis of the HRTEM images were carried out. We compared the obtained results with electrical transport measurements, and x-ray absorption spectroscopy conducted on the superlattices. The main results and highlights included the observation that the physical properties of LaNiO3 can be tuned by the relative layer thickness ratio of the superlattice components, resulting from differently reconstructed bond lengths and angles. This shows that clever choice of the second components and the adjustment of the thickness in a superlattice provide important mechanism for adjusting the properties in complex oxides.
Publications
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Atomic-scale investigation of nickelate-based perovskite superlattices, Poster presentation at Microscopy Conference 2023, Darmstadt
F. Misjak, R. Ortiz, D. Geiger, M.K. Kinyanjui, E. Benckiser & U. Kaiser
