Lattice dynamics in magnetic superelastic Ni-Mn-In alloys: Neutron scattering and ultrasonic experiments

Date
2009-06-30
Authors
Moya, Xavier
González-Alonso, David
Mañosa, Lluís
Planes, Antoni
Garlea, V.
Lograsso, Thomas
Schlagel, Deborah
Zarestky, Jerel
Aksoy, Seda
Acet, Mehmed
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Research Projects
Organizational Units
Ames Laboratory
Organizational Unit
Journal Issue
Series
Abstract

Neutron scattering and ultrasonic methods have been used to study the lattice dynamics of two single crystals of Ni-Mn-In Heusler alloys close to Ni50Mn34In16 magnetic superelastic composition. The paper reports on the experimental determination of the low-lying phonon-dispersion curves and the elastic constants for this alloy system. We found that the frequencies of the TA2 branch are relatively low and it exhibits a small dip anomaly at a wave number ξ0≈1/3, which softens with decreasing temperature. Associated with the softening of this phonon, we also observed the softening of the shear elastic constant C′=(C11−C12)/2. Both temperature softenings are typical for bcc-based solids which undergo martensitic transformations and reflect the dynamical instability of the cubic lattice against shearing of {110} planes along ⟨11̅ 0⟩ directions. Additionally, we measured low-lying phonon-dispersion branches and elastic constants in applied magnetic fields aimed to characterize the magnetoelastic coupling.

Description

This article is from Physical Review B 79 (2009): 214118, doi:10.1103/PhysRevB.79.214118.

Keywords
Citation
DOI
Collections