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Quantum Confinement and Surface Effects on the Itinerant Ferromagnetism in Ni and Ni–Fe Nanowire Arrays: An Ab Initio Study
Author(s) -
Ziti Ikram,
Britel Mohammed Réda,
Bouajaj Adel,
Wang Chumin
Publication year - 2018
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201700618
Subject(s) - ferromagnetism , magnetic moment , condensed matter physics , nanowire , ab initio , materials science , electron , ab initio quantum chemistry methods , quantum dot , density functional theory , nanotechnology , physics , chemistry , computational chemistry , quantum mechanics , molecule
Coordination number reduction of surface atoms and spatial confinement of itinerant electrons are decisive factors in the nano‐ferromagnetism. Impacts of these factors on the ferromagnetic moments of Ni and Ni–Fe nanowire (NW) arrays are quantified by means of the density functional theory through both atomic‐orbital and plane‐wave approaches. A systematic study of the wire diameter, interwire distance and chemical composition on the magnetic properties were carried out in eight thin nanowires to investigate the limiting cases of confinement and surface effects. The results reveal a growth of the magnetic moment when the wire diameter diminishes, due to the decrease of average coordination number which reduces the 3d electronic band width and then a larger spin population contrast. This fact is consistent with experimental data obtained from Ni nanoparticles and NWs. Moreover, we found a critical interwire distance, which is the minimum separation that maintains the individual NW magnetic moment. Finally, both local and global magnetic moments of Ni–Fe NWs obtained from the ab initio calculations are compared with experimental ones and a good consistency is observed.