uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
First-principles investigation of the composition dependent properties of Ni2+xMn1-xGa shape-memory alloys
Show others and affiliations
2010 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 82, no 2, 024201- p.Article in journal (Refereed) Published
Abstract [en]

The composition dependent lattice parameter, phase stability, elastic moduli, and magnetic transition temperature of the Ni2+xMn1-xGa shape-memory alloys are studied by using the first-principles exact muffin-tin orbital method in combination with the coherent potential approximation. The lattice parameter and tetragonal shear modulus of the cubic L-21 austenite phase decreases linearly with increasing concentration x of excess Ni atoms. The heats of formation of both cubic L-21 and tetragonal beta''' phases and their difference increase with x, indicating decreasing stability of the cubic and tetragonal phases and increasing driving force for the L-21 to beta''' martensitic transition. Investigating the electronic density of states, we find that the Ni-induced decreasing phase stability can mainly be ascribed to the weakening of the covalent bonding between minority spin states of Ni and Ga. Using the computed parameters, the composition dependence of the martensitic transition temperature is discussed. The theoretical Curie temperature, estimated from the Heisenberg model in combination with the mean-field approximation, is larger for the beta''' phase than for the L-21 phase. For both phases, the Curie temperature decreases nearly linearly with increasing x.

Place, publisher, year, edition, pages
2010. Vol. 82, no 2, 024201- p.
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-135802DOI: 10.1103/PhysRevB.82.024201ISI: 000279600400001OAI: oai:DiVA.org:uu-135802DiVA: diva2:375985
Available from: 2010-12-09 Created: 2010-12-08 Last updated: 2012-03-30Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Johansson, BörjeVitos, Levente
By organisation
Department of Physics and Astronomy
In the same journal
Physical Review B. Condensed Matter and Materials Physics
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 165 hits
ReferencesLink to record
Permanent link

Direct link