Anand, Kanika and Pulikkotil, J. J. and Auluck, S. (2014) Study of ferromagnetic instability in tau-MnAl, using first-principles. Journal of Alloys and Compounds, 601. 234-237. ISSN 0925-8388

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Abstract

The tau- phase of the binary Mn-Al system is a promising rare-earth free permanent magnet. However, the experimentally determined figure-of-merit (energy-factor) is significantly lower than the theoretical estimate. This is partly being associated with the low volume fraction of tau-MnAl during synthesis, chemical disorder driven inter-sublattice antiferromagnetism, and presence of multiple binary phases. In this work, with the help of first-principles linear response calculations, we show that the presumed long range ferromagnetic ordering in tau-MnAl is unstable. Calculation of Mn magnetic pair-exchange interaction for tau-MnAl show competing ferromagnetic and antiferromagnetic interactions. As a result, the study infers to a non-collinear magnetic ground state, which then partly explains the low magnetization as observed in experiments. Local probe experiments such as neutron diffraction, corroborating our prediction of the non-collinear state in tau-MnAl is therefore desired.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/S Elsevier.
Uncontrolled Keywords:	Magnetism DFT MnAl
Subjects:	Materials Science Metallurgy & Metallurgical Engineering
Divisions:	UNSPECIFIED
Depositing User:	Dr. Rajpal Walke
Date Deposited:	20 Nov 2015 06:13
Last Modified:	20 Nov 2015 06:13
URI:	http://npl.csircentral.net/id/eprint/1563

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