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Updated: Jun 13, 2025
09:41
Bulk and Thin Film Synthesis of Compositionally Variant Entropy-stabilized Oxides
Published on: May 29, 2018
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Impact of Synthesis Method on the Structure and Function of High Entropy Oxides
Mario U González-Rivas1,2, Solveig S Aamlid2, Megan R Rutherford1,2
1Department of Physics & Astronomy, University of British Columbia, Vancouver V6T 1Z1, British Columbia, Canada.
Journal of the American Chemical Society
|September 10, 2024
Summary
High entropy oxides (HEOs) show varied properties based on synthesis method, not just composition. Combustion synthesis yields ideal cation homogeneity, impacting magnetic properties and offering new optimization pathways.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Nanotechnology
Background:
- Sample dependence, where identical materials show different properties, is a challenge in materials science.
- High entropy oxides (HEOs) are particularly susceptible due to their complex chemistry.
- Controlling synthesis is key to understanding and mitigating sample dependence.
Purpose of the Study:
- To investigate the impact of diverse synthesis methods on the structural and magnetic properties of a single spinel High Entropy Oxide (HEO).
- To correlate microstructural and local structural variations with observed functional property differences.
- To establish synthesis method as a critical parameter for optimizing HEOs.
Main Methods:
- Preparation of a spinel HEO using five distinct methods: solid state, high pressure, hydrothermal, molten salt, and combustion synthesis.
- Comprehensive structural characterization using various X-ray techniques across multiple length scales.
- Magnetic property measurements to assess functional differences.
Main Results:
- While average crystal structure remained consistent, local structures and microstructures varied significantly across synthesis methods.
- Intermediate length scales revealed notable differences in crystallite morphology and cation homogeneity.
- Combustion synthesis produced ideal cation homogeneity, unlike other methods.
- Magnetic properties, including transition sharpness, saturation moment, and coercivity, showed marked dependence on the synthesis route.
Conclusions:
- Synthesis method profoundly influences the microstructure and properties of High Entropy Oxides (HEOs), even for identical nominal compositions.
- The chemical flexibility of HEOs is coupled with strong synthesis dependence, offering a tunable parameter for material design.
- Understanding and controlling synthesis-dependent variations are crucial for realizing the full potential of HEOs in various applications.
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