Chemical Environment and Structural Variations in High Entropy Oxide Thin Film Probed with Electron Microscopy

We employ analytical transmission electron microscopy (TEM) to correlate the structural and chemical environment variations within a stacked epitaxial thin film of the high entropy oxide (HEO) Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O (J14), with two layers grown at different substrate temperatures (500 and 200 °C) using pulsed laser deposition (PLD). Electron diffraction and atomically resolved STEM imaging reveal the difference in out-of-plane lattice parameters in the stacked thin film, which is further quantified on a larger scale using four-dimensional STEM (4D-STEM). In the layer deposited at a lower temperature, electron energy loss spectroscopy (EELS) mapping indicates drastic changes in the oxidation states and bonding environment for Co ions, and energy-dispersive X-ray spectroscopy (EDX) mapping detects more significant cation deficiency. Ab initio density functional theory (DFT) calculations validate that vacancies on the cation sublattice of J14 result in significant electronic and structural changes. The experimental and computational analyses indicate that low temperatures during film growth result in cation deficiency, an altered chemical environment, and reduced lattice parameters while maintaining a single phase. Our results demonstrate that the complex correlation of configurational entropy, kinetics, and thermodynamics can be utilized for accessing a range of metastable configurations in HEO materials without altering cation proportions, enabling further engineering of functional properties of HEO materials.

Files

Metadata

Work Title Chemical Environment and Structural Variations in High Entropy Oxide Thin Film Probed with Electron Microscopy
Access
Open Access
Creators
  1. Leixin Miao
  2. Jacob T. Sivak
  3. George Kotsonis
  4. Jim Ciston
  5. Colin L. Ophus
  6. Ismaila Dabo
  7. Jon Paul Maria
  8. Susan B. Sinnott
  9. Nasim Alem
Keyword
  1. High Entropy Oxides
  2. Transmission Electron Microscopy
  3. 4D-STEM
  4. Electron Energy Loss Spectroscopy
  5. Pulsed Laser Deposition
  6. Density Functional Theory
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. ACS Nano
Publication Date May 31, 2024
Publisher Identifier (DOI)
  1. https://doi.org/10.1021/acsnano.4c00787
Deposited October 24, 2024

Versions

Analytics

Collections

This resource is currently not in any collection.

Work History

Version 1
published

  • Created
  • Added Chemical_Environment_and_Structural_Variations_in_HEO_Thin_Film_Probed_with_Electron_Microscopy.pdf
  • Added Creator Leixin Miao
  • Added Creator Jacob T. Sivak
  • Added Creator George Kotsonis
  • Added Creator Jim Ciston
  • Added Creator Colin L. Ophus
  • Added Creator Ismaila Dabo
  • Added Creator Jon Paul Maria
  • Added Creator Susan B. Sinnott
  • Added Creator Nasim Alem
  • Published
  • Updated
  • Updated Keyword, Publication Date Show Changes
    Keyword
    • High Entropy Oxides, Transmission Electron Microscopy, 4D-STEM, Electron Energy Loss Spectroscopy, Pulsed Laser Deposition, Density Functional Theory
    Publication Date
    • 2024-06-11
    • 2024-05-31