Publication Type
Journal
Journal Name
Materials Science and Engineering A
Publication Date
Page Number
227
Volume
481-482
Abstract
We have studied the lattice dynamics of a Ni54Mn23Al23 (at.%) Heusler single-crystalline alloy by means of neutron scattering and ultrasonic techniques. Results show the existence of a number of precursor phenomena. We have found an anomaly (dip) in the low TA2 phonon branch at the wave number ����0.33 (in reciprocal lattice units) that becomes more pronounced (phonon softening) with decreasing temperature. We have also observed softening of the associated shear elastic constant (C��) with decreasing temperature. Ultrasonic measurements under applied magnetic field, both isothermally and varying the temperature show that the values of elastic constants depend on magnetic order thus evidencing magnetoelastic coupling.
