Magnetoelastic effects in Ni2Mn1+xGa1-x alloys from first-principles calculations
2010 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 81, no 6, 064108-1-064108-5 p.Article in journal (Refereed) Published
The magnetic coupling between Mn atoms on Ga sublattice (Mn-Ga) and Mn atoms on Mn sublattice (Mn-Mn) in Ni2Mn1+xGa1-x alloy and its effect on the elastic modulus of the alloy are investigated by the use of first-principles methods. It is shown that, for x = 0.25, the state with antiparallel Mn-Ga-Mn-Mn magnetic coupling is slightly more stable than that with parallel coupling, whereas for x = 0.10, both magnetic states are almost degenerated. For both antiparallel and parallel Mn-Ga-Mn-Mn magnetic couplings, the bulk modulus (B) of Ni2Mn1+xGa1-x deviates from the general e/a-B relationship with e/a being the number of valence electrons per atom. The shear modulus C' versus the martensitic transformation temperature T-M for Ni2Mn1+xGa1-x with antiparallel Mn-Ga-Mn-Mn magnetic coupling is in line with the general C'-T-M relationship for Ni2MnGa-based alloys, in contrast to the case of parallel Mn-Ga-Mn-Mn magnetic coupling.
Place, publisher, year, edition, pages
2010. Vol. 81, no 6, 064108-1-064108-5 p.
shape-memory alloys, electronic-structure, martensitic phase, potential, model, heusler alloys, ni2mnga, transformation, approximation, strain
IdentifiersURN: urn:nbn:se:kth:diva-19262DOI: 10.1103/PhysRevB.81.064108ISI: 000274998100037ScopusID: 2-s2.0-77954823239OAI: oai:DiVA.org:kth-19262DiVA: diva2:337309
FunderSwedish Research Council
QC 201005252010-08-052010-08-052011-08-30Bibliographically approved