Original title:
Quantum-mechanical study of magnetic properties of superalloy nanocomposite phase Fe2AlTi
Authors:
Slávik, Anton ; Miháliková, Ivana ; Friák, Martin ; Všianská, Monika ; Šob, Mojmír Document type: Papers Conference/Event: NANOCON 2017. International Conference on Nanomaterials - Research & Application /9./, Brno (CZ), 20171018
Year:
2018
Language:
eng Abstract:
The L21-structure Fe2AlTi intermetallic compound is one of the two phases identified in Fe-Al-Ti superalloy nanocomposites. Experimental data related to low-temperature magnetic properties of this Heusler compound indicate that magnetic moment is about 0.1 Bohr magneton per formula unit. In contrast, previous quantum-mechanical calculations predicted Fe2AlTi to have much higher magnetic moment, 0.9 Bohr magneton per formula unit. In order to solve this discrepancy between the theory and experiment we have performed a series of quantum-mechanical fix-spin-moment calculations and compared our results with those for non-magnetic state. It turns out that the total energy of the non-magnetic state is only by 10.73 meV/atom higher than that of the magnetic state. When applying Boltzmann statistics to this very small energy difference we predict that the non-magnetic state appears at non-zero temperatures with significant probabilities (for instance, 22.36 % at T = 100 K) and reduces the overall magnetic moment. As another mechanism lowering the magnetization we studied selected shape deformations, in particular trigonal shearing. Fe2AlTi exhibits a compression-tension asymmetry with respect to these strains and, for example, the strain 0.08 destabilizes the spin-polarized state, leaving the non-magnetic state as the only stable one.
Keywords:
Ab initio calculations; Fe-Al based superalloys; Fixed-spin-moment; Nanocomposites Project no.: LM2015069 (CEP), GA17-22139S (CEP), GA16-24711S (CEP) Funding provider: GA MŠk, GA ČR, GA ČR Host item entry: NANOCON 2017: Conference Proceedings, ISBN 978-80-87294-81-9

Institution: Institute of Physics of Materials AS ČR
(web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences. Original record: http://hdl.handle.net/11104/0289458