Glassy phonon heralds a strain glass state in a shape memory alloy P. J. Stonaha, I. Karaman, R. Arroyave [et al.]
Material type:
ArticleSubject(s): сплавы с памятью формы | фононное стекло | деформацияGenre/Form: статьи в журналах Online resources: Click here to access online
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Physical Review Letters Vol. 120, № 24. P. 245701-1-245701-5Abstract: 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 longrange
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.
Библиогр.: 34 назв.
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 longrange
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.
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