Origin of magnetic interactions and their influence on the structural properties of Ni2MnGa and related compounds

Details Origin of magnetic interactions and their influence on the structural properties of Ni2MnGa and related compounds Origin of magnetic interactions and their influence on the structural properties of Ni2MnGa and related compounds

2012-03-07

arxiv.org/abs/1203.1553v1

J. Phys.: Condens. Matter 24, 185501, (2012)

Physics

Condensed Matter

Materials Science

16 pages, 25 figures

Scientific paper

10.1088/0953-8984/24/18/185501

In this work, we perform first principles DFT calculations to investigate the interplay between magnetic and structural properties in Ni2MnGa. We demonstrate that the relative stability of austenite (cubic) and non-modulated martensite (tetragonal) phases depends critically on the magnetic interactions between Mn atoms. While standard approximate DFT functionals stabilize the latter phase, a more accurate treatment of electronic localization and magnetism, obtained with DFT+U, suppresses the non-modulated tetragonal structure for the stoichiometric compound, in better agreement with the experiments. We show that the Anderson impurity model, with Mn atoms treated as magnetic impurities, can explain this observation and that the fine balance between super-exchange RKKY type interactions mediated by Ni d and Ga p orbitals determines the equilibrium structure of the crystal. The Anderson model is also demonstrated to capture the effect of the number of valence electrons per unit cell on the structural properties, often used as an empirical parameter to tune the behavior of Ni2MnGa based alloys. Finally, we show that off-stoichiometric compositions with excess Mn promote transitions to a non-modulated tetragonal structure, in agreement with experiments.

Affiliated with

Also associated with

No associations

Rating

Origin of magnetic interactions and their influence on the structural properties of Ni2MnGa and related compounds does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Origin of magnetic interactions and their influence on the structural properties of Ni2MnGa and related compounds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Origin of magnetic interactions and their influence on the structural properties of Ni2MnGa and related compounds will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-395296