Dynamic polymorphism in solids with multiple local minima on the atomic potential energy surface

ORAL

Abstract

Polymorphic solids of the same chemical composition can have different atomic structures. If transformations to other structures have sufficiently high enthalpy barriers, then each structure is either stable or metastable: it is stationary and does not spontaneously change with time. But what happens, if those barriers are low? As examples, we consider NiTi and FeRh alloys exhibiting large elasto-caloric and magneto-caloric effects. We suggest a model for dynamically polymorphic solids, consider an atomic structure stabilized by entropy, and compare theoretical predictions to experimental observations.

*Predictive methods development was partially funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. Application to caloric materials discovery at Ames Laboratory is supported by the U.S. DOE, Advanced Manufacturing Office of th

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Presenters

  • Nikolai Zarkevich

    • Department of Energy, Ames Laboratory

Authors

  • Nikolai Zarkevich

    • Department of Energy, Ames Laboratory

  • Duane Johnson

    • Iowa State University
    • Iowa state university/Ames Laboratory
    • Iowa State University / Ames Laboratory

  • Vitalij Pecharsky

    • Iowa State University
    • Ames Laboratory, U.S. Department of Energy, and Department of Materials Science and Engineering, Iowa State University
    • Materials Sceince and Engineering, Ames Laboratory
    • Division of Materials Science and Engineering, Ames Laboratory
    • Ames Laboratory