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

作     者：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 

作者机构：Material Science and Technology Division Oak Ridge National Lab Oak Ridge Tennessee 37831 USA Department of Material Science and Engineering Texas A&M University College Station Texas 77843 USA Department of Mechanical Engineering Texas A&M University College Station Texas 77843 USA Neutron Scattering Division Oak Ridge National Lab Oak Ridge Tennessee 37831 USA Siberian Physical Technical Institute Tomsk State University Tomsk 634050 Russia 

出 版 物：《Physical Review Letters》 (物理评论快报)

年 卷 期：2018年第120卷第24期

页      面：245701-245701页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：Metals and Metallic Nanostructures Program Office of Basic Energy Sciences U.S. National Science Foundation National Science Foundation, NSF, (1508634) U.S. Department of Energy, USDOE Division of Materials Research, DMR Division of Materials Sciences and Engineering, DMSE 

主　　题：Ferroelasticity Phase transitions Phonons Shape memory effect Neutron scattering Scanning tunneling microscopy Time-of-flight neutron spectroscopy 

摘      要：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.