|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Hume-Rothery Symposium on Connecting Macroscopic Materials Properties to Their Underlying Electronic Structure: The Role of Theory, Computation, and Experiment
||Turning Ab Initio Simulations into Surprising Bulk Predictions
||Elizabeth Decolvenaere, Emily Levin, Ram Seshadri, Alexander G Donchev, John L Klepeis, Anton Van der Ven, David E Shaw
|On-Site Speaker (Planned)
Magnetic exchange hardening, a phenomenon that increases a material's resistance to demagnetization, typically occurs in two-phase mixtures consisting of a ferromagnetic phase and an antiferromagnetic phase. We demonstrate the unique case of exchange hardening in a single, chemically-disordered full-Heusler alloy: Mn(1-x)Fe(x)Ru2Sn. Using nanoscale ab initio calculations, we parameterized a chemomagnetic cluster expansion Hamiltonian suitable for Monte Carlo simulations containing thousands of interacting sites and capable of describing bulk magnetic and chemical behavior. In our simulations, we find that nanoscale fluctuations in composition (as expected in any disordered phase) result in antiferromagnetic pockets in a bulk ferromagnetic system, complete with separate Neel and Curie temperatures of (anti)ferromagnetic ordering that match experimental observations. I will also briefly discuss how similarly simple ab initio calculations on small molecular systems can be used to parameterize accurate force fields, which can be used in molecular dynamics simulations to link the nanoscale and the mesoscale.
||Modeling and Simulation, Magnetic Materials, Computational Materials Science & Engineering