Author/Authors :
Moya، نويسنده , , X. and Maٌosa، نويسنده , , Ll and Planes، نويسنده , , A. and Krenke، نويسنده , , T. and Acet، نويسنده , , M. and Wassermann، نويسنده , , E.F. and Morin، نويسنده , , M. and Garlea، نويسنده , , V.O. and Lograsso، نويسنده , , T.A. and Zarestky، نويسنده , , J.L.، نويسنده ,
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 ξ 0 ≈ 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.
Keywords :
precursor phenomena , Magnetoelastic coupling , Ni–Mn–Al , Heusler alloy , neutron scattering , elastic constants
