J Phys Condens Matter. 2010 Sep 01;22(34):346001. doi: 10.1088/0953-8984/22/34/346001. Epub 2010 Aug 02.

Complex magnetic interactions in off-stoichiometric NiMnGa alloys.

Journal of physics. Condensed matter : an Institute of Physics journal

Subhradip Ghosh, Biplab Sanyal

PMID: 21403266 DOI: 10.1088/0953-8984/22/34/346001

Abstract

Using first-principles density functional theory, the magnetic pair interactions between various pairs of chemical specie have been calculated and the trends in magnetism with varying compositions and chemical ordering are analyzed for three off-stoichiometric NiMnGa alloys in their austenite phases. The experimentally observed trend of decreasing magnetization with increasing Mn concentration is attributed to the antiferromagnetic interactions among Mn atoms occupying sublattices other than the original Mn one. The role of chemical ordering on magnetization is also analyzed by total energy results and exchange interactions. We are able to explain the recently published neutron scattering experiments with our theoretical analyses.

Publication Types

• Journal Article
• Research Support, Non-U.S. Gov't