TY - JOUR
T1 - Lattice dynamics in magnetic superelastic Ni-Mn-In alloys
T2 - Neutron scattering and ultrasonic experiments
AU - Moya, Xavier
AU - González-Alonso, David
AU - Mañosa, Lluís
AU - Planes, Antoni
AU - Garlea, V. O.
AU - Lograsso, T. A.
AU - Schlagel, D. L.
AU - Zarestky, J. L.
AU - Aksoy, Seda
AU - Acet, Mehmet
PY - 2009/6/30
Y1 - 2009/6/30
N2 - 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 Ni50 Mn34 In16 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 1 1̄ 0 directions. Additionally, we measured low-lying phonon-dispersion branches and elastic constants in applied magnetic fields aimed to characterize the magnetoelastic coupling.
AB - 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 Ni50 Mn34 In16 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 1 1̄ 0 directions. Additionally, we measured low-lying phonon-dispersion branches and elastic constants in applied magnetic fields aimed to characterize the magnetoelastic coupling.
UR - http://www.scopus.com/inward/record.url?scp=68949094322&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.79.214118
DO - 10.1103/PhysRevB.79.214118
M3 - Article
AN - SCOPUS:68949094322
SN - 1098-0121
VL - 79
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 21
M1 - 214118
ER -