Lattice dynamics of Ni-Mn-Al Heusler alloys

TitleLattice dynamics of Ni-Mn-Al Heusler alloys
Publication TypeJournal Article
Year of Publication2008
AuthorsMoya X, Manosa L, Planes A, Krenke T, Acet A, Wassermann EF, Morin M, Garlea VO, Lograsso TA, Zarestky JL
Journal TitleMaterials Science and Engineering a-Structural Materials Properties Microstructure and Processing
Date PublishedMay
Type of ArticleProceedings Paper
ISBN Number0921-5093
Accession NumberISI:000255716100044
Keywordselastic constants, FERROMAGNETIC NI2MNGA, Heusler alloy, magnetoelastic coupling, MARTENSITIC PHASE, neutron scattering, Ni-Mn-Al, precursor phenomena, premartensitic phenomena, transition

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 TA(2) phonon branch at the wave number xi(0) approximate to 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. (C) 2007 Elsevier B.V. All rights reserved.

Alternate JournalMater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process.