Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
Maria Gazda
Institute of Nanotechnology and Materials Engineering, and Advanced Materials Centre, Gdańsk University of Technology, Gdańsk, Poland
Veerle Keppens
Department of Materials Science and Engineering, University of Tennessee Knoxville, Knoxville, Tennessee 37916, USA
Alessandro R. Mazza
Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87185, USA
Scott J. McCormack
Department of Materials Science and Engineering, University of California Davis, Davis, California 95616, USA
Aleksandra Mielewczyk-Gryń
Institute of Nanotechnology and Materials Engineering, and Advanced Materials Centre, Gdańsk University of Technology, Gdańsk, Poland
Brianna Musico
Sigma Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87185, USA
Katharine Page
Department of Materials Science and Engineering, University of Tennessee Knoxville, Knoxville, Tennessee 37916, USA
Christina M. Rost
Department of Physics and Astronomy, James Madison University, Harrisonburg, Virginia 22807, USA
Susan B. Sinnott
Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
Cormac Toher
Department of Materials Science and Engineering and Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, USA
Thomas Z. Ward
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
Ayako Yamamoto
Graduate School of Science and Technology, Shibaura Institute of Technology, Tokyo, Japan
High entropy oxides are emerging as an exciting new avenue to design highly tailored functional behaviors that have no traditional counterparts. Study and application of these materials are bringing together scientists and engineers from physics, chemistry, and materials science. The diversity of each of these disciplines comes with perspectives and jargon that may be confusing to those outside of the individual fields, which can result in miscommunication of important aspects of research. In this Perspective, we provide examples of research and characterization taken from these different fields to provide a framework for classifying the differences between compositionally complex oxides, high entropy oxides, and entropy stabilized oxides, which is intended to bring a common language to this emerging area. We highlight the critical importance of understanding a material’s crystallinity, composition, and mixing length scales in determining its true definition.
