Epitaxial stabilization of ultra thin films of high entropy perovskite

Abstract

High entropy oxides (HEOs) are a class of materials, containing equimolar portions of five or more transition metal and/or rare-earth elements. We report here about the layer-by-layer growth of HEO [(La${}_{0.2}$Pr${}_{0.2}$Nd${}_{0.2}$Sm${}_{0.2}$Eu${}_{0.2}$)NiO${}_3$] thin films on NdGaO${}_3$ substrates by pulsed laser deposition. The combined characterizations with in-situ reflection high energy electron diffraction, atomic force microscopy, and X-ray diffraction affirm the single crystalline nature of the film with smooth surface morphology. The desired +3 oxidation of Ni has been confirmed by an element sensitive X-ray absorption spectroscopy measurement. Temperature dependent electrical transport measurements revealed a first order metal-insulator transition with the transition temperature very similar to the undoped NdNiO${}_3$. Since both of these systems have a comparable tolerance factor, this work demonstrates that the electronic behaviors of $A$-site disordered perovskite-HEOs are primarily controlled by the average tolerance factor.

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References in corpus (8)

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Cited by in corpus (1)

• Unexpected crystalline homogeneity from the disordered bond network in La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 films