Glassy Phonon Heralds a Strain Glass State in a Shape Memory Alloy

P. J. Stonaha, I. Karaman, R. Arroyave, D. Salas, N. M. Bruno, Y. Wang, M. F. Chisholm, S. Chi, D. L. Abernathy, Y. I. Chumlyakov, M. E. Manley

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Abstract

Shape memory strain glasses are frustrated ferroelastic materials with glasslike slow relaxation and nanodomains. It is possible to change a NiCoMnIn Heusler alloy from a martensitically transforming alloy to a nontransforming strain glass by annealing, but minimal differences are evident in the short- or long-range order above the transition temperature - although there is a structural relaxation and a 0.18% lattice expansion in the annealed sample. Using neutron scattering we find glasslike phonon damping in the strain glass but not the transforming alloy at temperatures well above the transition. Damping occurs in the mode with displacements matching the martensitic transformation. With support from first-principles calculations, we argue that the strain glass originates not with transformation strain pinning but with a disruption of the underlying electronic instability when disorder resonance states cross the Fermi level.

Original languageEnglish
Article number245701
JournalPhysical Review Letters
Volume120
Issue number24
DOIs
StatePublished - Jun 11 2018

Funding

Research sponsored by the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. A portion of this research used resources at the High Flux Isotope Reactor and Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. I. K., N. M. B., D. S., and R. A. acknowledge the financial support from the U.S. National Science Foundation, Division of Materials Research, Metals and Metallic Nanostructures Program, Grant No. 1508634.

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