Impact of Entropy Stabilization on Electrical Conductivity
Entropy-stabilized oxide (ESO) research has primarily focused on discovering unprecedented structures, chemistries, and properties in the single-phase state. However, few studies discuss the impacts of entropy stabilization and secondary phases on functionality and in particular, electrical conductivity. The IRG 1 collaborative work between Bowman (Hasti Vahidi), Schoenung (Justin Cortez and Alex Dupuy) and Rupert (Pulkit Garg) research groups, revealed the structure, composition, and morphology of the secondary phases and interfaces formed by heat treatment of (Co,Cu,Ni,Zn,Mg)O via scanning transmission electron microscopy (STEM).
You can also click this link to watch a YouTube presentation by Hasti Vahidi, a MRSEC funded JRF and the first author of this publication.
The observed phase transformation motivated the team to explore the changes in electrical conductivity, as defect chemistry changes with phase evolutions, potentially creating new charge carriers or pathways for electrical conduction. The observations suggest an enhanced electronic conductivity through grain interiors, as secondary phases segregate to the grain boundaries (GBs), thereby increasing the concentration of charge carrying defects in the grains. This work demonstrated the potential to selectively grow secondary phases in ESO grains and at GBs, thereby tuning the electrical properties using microstructure design, nanoscale engineering, and heat treatment, paving the way to develop many novel materials. The work has been published in the journal of Advanced Functional Materials. Learn more