About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
2025 Undergraduate Student Poster Contest
|
| Presentation Title |
SPU-25: Maximizing Size-Misfit Cation Solubility in Rock Salt High-Entropy Oxides |
| Author(s) |
Joseph A. Petruska, Matthew Furst, Dhiya Srikanth, Kaylin Lamaute, Jon-Paul Maria, Saeed S. I. Almishal |
| On-Site Speaker (Planned) |
Joseph A. Petruska |
| Abstract Scope |
We explore and quantitatively map the cation-size mismatch solubility limits in high-entropy oxides (HEOs), by reporting on Ca˛⁺ substitution in prototypical MgCoNiCuZnO, because while isovalent, Ca˛⁺ is 38% larger than its partners’ average ionic radii. Using the thermodynamics-grounded bond-length distribution descriptor, we identify Ca2+–Cu2+ interactions as the primary prospective lattice destabilizer. We use X-ray diffraction to identify single-phase rock salt formation. Bulk synthesis confirms only 4% Ca solubility with Cu at 950ēC, modestly rising to 5% after Cu removal at 1150ēC. We then employ far-from-equilibrium pulsed laser deposition to investigate metastable solubility; epitaxial films incorporate 10% Ca with Cu and a full 20% Ca without, doubling and quadrupling the respective bulk limits. |