Local magnetic interactions in Cadmium-doped Cobalt allotropic phases by first principles calculation
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2019
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JOINT MMM-INTERMAG CONFERENCE
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Cobalt is one of the most attractive ferromagnetic material at room temperature. While Co is used in industrial processes of catalysis, in fundamental
science, the connection between the different crystal structure with magnetic
properties of Co has attained the attention. Co can crystallize in four different
structures: hexagonal closed-packed (hcp, alpha), face-centered cubic (fcc,
beta), primitive cubic (epsilon), and body-centered cubic (bcc). The hcp and
fcc phases are stable in bulk and nanostructured samples and the difference in
their formation energy is small so that, even under small variations of temperature and/or pressure conditions, hcp and fcc can interexchange easily. Often,
the literature reports the co-existence of both structures. In last years, new routes of the synthesis and improvement in previous methods have allowed the production of nanostructured Cobalt samples with Epsilon and bcc crystalline
phases, which under usual conditions are metastable. The magnetic properties
vary with the structure differences in their electronic structure, e.g. the hcp
phase has higher coercivity, whereas the fcc is a soft magnet In the work here
reported, first-principles calculations were performed in the four Co structures
in order to investigate one sensitive and quite local parameter: the magnetic
hyperfine field (mhf). We have used Augmented Planes Waves plus local
orbitals (APW+lo) all-electron method based on the density functional theory
and implemented in the WIEN2k code to simulate supercells of Co doped
with Cd. The resulting mhf at Cd ions is compared with values from perturbed
angular correlation spectroscopy measurements using 111Cd as probe nuclei
found in the literature for hcp, fcc, and bcc phases. Up to date, experimental
results for mhf at 111Cd for epsilon structure are not available. Calculated mhf
and magnetic moments agree well with reported experimental values - tab. 1.
From the calculated density of states for each structure, it is possible to investigate
the differences in the magnetic exchange interaction at an atomic view
Como referenciar
PEREIRA, L.F.; CARBONARI, A.W. Local magnetic interactions in Cadmium-doped Cobalt allotropic phases by first principles calculation. In: JOINT MMM-INTERMAG CONFERENCE, January 14-18, 2019, Washington, DC, USA. Abstract... Melville, NY, USA; Piscataway, NJ, USA: AIP Publishing; IEEE Magnetics, 2019. p. 600-600. Disponível em: http://repositorio.ipen.br/handle/123456789/30974. Acesso em: 06 Feb 2025.
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