Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/86018
Type: Artigo
Title: Magnetic moment of Fe3O4 films with thicknesses near the unit-cell size
Author: Gomes, G. F. M.
Bueno, T. E. P.
Parreiras, D. E.
Abreu, G. J. P.
Siervo, A. de
Cezar, J. C.
Pfannes, H. D.
Paniago, R.
Abstract: We perform a systematic study on the evolution of the magnetic spin moment (ms) of epitaxial [100]- and [111]-magnetite films of increasing thickness. The ultrathin films are characterized by low-energy electron diffraction, x-ray absorption spectroscopy, and x-ray magnetic circular dichroism (XMCD). By employing sum rules on the XMCD spectra we obtain ms=3.6 μB/f.u. for samples of around 35 Å. This is considered a bulk value and has been reported only for films more than 10 times thicker. Moreover, we show that even 10-Å-thick magnetite already presents a significant magnetic moment. For both grown directions the moment increases similarly with the thickness. The ferromagnetic behavior for each iron ion site (Feocta2+, Feocta3+, Fetetra3+) of Fe3O4 is measured by monitoring XMCD peaks. The deduced hysteresis curves (per ion, per site) exhibit a coercive field of 300 Oe. Our results show that both the ferrimagnetic order and the bulk moment value are preserved at room temperature around the thickness of 2 unit cells.
We perform a systematic study on the evolution of the magnetic spin moment (ms) of epitaxial [100]- and [111]-magnetite films of increasing thickness. The ultrathin films are characterized by low-energy electron diffraction, x-ray absorption spectroscopy, and x-ray magnetic circular dichroism (XMCD). By employing sum rules on the XMCD spectra we obtain ms=3.6 μB/f.u. for samples of around 35 Å. This is considered a bulk value and has been reported only for films more than 10 times thicker. Moreover, we show that even 10-Å-thick magnetite already presents a significant magnetic moment. For both grown directions the moment increases similarly with the thickness. The ferromagnetic behavior for each iron ion site (Feocta2+, Feocta3+, Fetetra3+) of Fe3O4 is measured by monitoring XMCD peaks. The deduced hysteresis curves (per ion, per site) exhibit a coercive field of 300 Oe. Our results show that both the ferrimagnetic order and the bulk moment value are preserved at room temperature around the thickness of 2 unit cells.
Subject: Ferro
Filmes ultra-finos
Espectroscopia de raio X
Country: Estados Unidos
Editor: American Physical Society
Citation: Physical Review B - Condensed Matter And Materials Physics. American Physical Society, v. 90, n. 13, p. - , 2014.
Rights: aberto
Identifier DOI: 10.1103/PhysRevB.90.134422
Address: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.134422
Date Issue: 2014
Appears in Collections:IFGW - Artigos e Outros Documentos

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