We use quantum-mechanical calculations to test a hypothesis of Glover et al. (J. Mag. Mag. Mater. 15 (1980) 699) that Co atoms in the Fe 2 AlCo compound have on average 3 Fe and 3 Co atoms in their second nearest neighbor shell. We have simulated four structural configurations of Fe 2 AlCo including the full Heusler structure, inverse Heusler polymorph and two other phases matching this idea. The highest thermodynamic stability at = 0 K is indeed predicted for one of the phases with the distribution of atoms according to Glover and et al. However, small energy differences among three of the studied polymorphs lead to a disordered CsCl-structure-like (B2-like) phase at elevated temperatures. The fourth variant, the full Heusler phase, is predicted to be mechanically unstable. The global magnetic states are predicted to be ferromagnetic but local magnetic moments of Fe and Co atoms sensitively depend on the composition of the first and second coordination shells.
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http://dx.doi.org/10.3390/ma11091543 | DOI Listing |
Materials (Basel)
January 2025
Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
Manganese-based alloys with the composition MnFeZ (Z = Si, Al) have been extensively investigated in recent years due to their potential applications in spintronics. The MnFeSi alloy, prepared in the form of ingots, powders, or ribbons, exhibits either a cubic full-Heusler (2) structure, an inverse-Heusler (XA) structure, or a combination of both. In contrast, the MnFeAl alloy has so far been synthesized only in the form of ingots, featuring a primitive cubic (β-Mn type) structure.
View Article and Find Full Text PDFiScience
December 2024
College of Physical Science and Technology, Guangxi University, Nanning 530004, P.R. China.
Half-metallic materials are widely used as spintronic devices such as electrodes, magnetic tunneling junction, and giant magnetoresistance. In this work, we have systematically investigated the structural stability, Gilbert damping, electronic structure, and magnetism together with exchange interactions and Curie temperatures for MnTaAl and MnWAl alloys. Initially, we estimate their structural stability and offer possible phase synthesis.
View Article and Find Full Text PDFPhys Chem Chem Phys
October 2024
Department of Physics, Michigan Technological University, Houghton, Michigan 49931, USA.
Half-metallic Co-based full Heusler alloys have captured considerable attention of researchers in the realm of spintronic applications, owing to their remarkable characteristics such as exceptionally high spin polarization at the Fermi level, ultra-low Gilbert damping, and a high Curie temperature. In this comprehensive study, employing the density functional theory, we delve into the electronic stability and ballistic spin transport properties of a magnetic tunneling junction (MTJ) comprising a CoMnSb/HfIrSb interface. An in-depth investigation of -dependent spin transmissions uncovers the occurrence of coherent tunneling for the Mn-Mn/Ir interface, particularly when a spacer layer beyond a certain thickness is employed.
View Article and Find Full Text PDFAdv Sci (Weinh)
October 2024
Interdisciplinary Materials Research Center, School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China.
Doping narrow-gap semiconductors is a well-established approach for designing efficient thermoelectric materials. Semiconducting half-Heusler (HH) and full-Heusler (FH) compounds have garnered significant interest within the thermoelectric field, yet the number of exceptional candidates remains relatively small. It is recently shown that the vacancy-filling approach is a viable strategy for expanding the Heusler family.
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