Session Y22: Ferroelectric and Structural Phase Transitions
8:00 AM–11:00 AM, Friday, March 25, 2011
Room: D163
Sponsoring Unit:
DCMP
Chair: Jason Lashley, Los Alamos National Laboratory
Abstract ID: BAPS.2011.MAR.Y22.10
Abstract: Y22.00010 : Structural and magnetic properties of Ni$_2$MnGa from first-principles
9:48 AM–10:00 AM
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Abstract 
Authors:
Vamshi Katukuri
(CEMS University of Minnesota)
Burak Himmetoglu
(CEMS University of Minnesota)
Matteo Cococcioni
(CEMS University of Minnesota)
Ni$_2$MnGa is the prototype magnetic shape-memory alloy. In this work we use ab-initio calculations to characterize structural and magnetic transitions and to identify possible strategies to tune them towards the same critical point. To this aim both the austenite and the martensite phases of the Ni$_2$MnGa alloy are studied with particular attention to the electronic factors controlling their stability and the onset of the structural transition. Our results indicate that, in spite of its metallic character, electronic correlations play an important role in determining the behavior of this compound and, in particular, the entity (and sign) of the deformation accompanying the transition from the austenite phase to the martensite one. The vibrational properties of the austenite phase are also studied and structural instabilities (soft modes) are investigated as possible signatures of intermediate ``modulated'' structures.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.Y22.10