G. Velleaud

Institut Universitaire de France, Lutetia Parisorum, Île-de-France, France

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Publications (7)9.56 Total impact

  • G. Velleaud · B. Sangare · M. Mercier · G. Aubert ·
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    ABSTRACT: Y.I.G. exhibits electric field dependent magnetic properties which have been measured as a function of temperature and of the applied magnetic field. These magnetoelectric properties are discussed on the basis of the macroscopic model recently proposed by one of us and a remarkable agreement is found between theory and experiment.
    Solid State Communications 10/1984; 52(1):71–74. DOI:10.1016/0038-1098(84)90721-X · 1.90 Impact Factor
  • G. Velleaud · B. Sangare · M. Mercier ·
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    ABSTRACT: In ferrimagnetic garnet YIG the magnetoelectric (me) effect is bound to the magnetization process, and so to the applied magnetic field. Thus we can interpret the me susceptibility with the help of a phenomenological model characterized by two constants c = 7.9 × 10-9 and d = -2.5 × 10-8 in reduced coordinates.
    Journal of Magnetism and Magnetic Materials 02/1983; 31:865-866. DOI:10.1016/0304-8853(83)90717-5 · 1.97 Impact Factor
  • G. Velleaud · M. Mercier · G. Aubert ·
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    ABSTRACT: The magnetoelectric effects in Fe5LiO8 are investigated for different experimental configurations. The results are discussed in the frame of a new theoretical model which demonstrates the important role played by the magnetic domains and the magnetization processes.
    Solid State Communications 12/1982; 44(9):1387–1391. DOI:10.1016/0038-1098(82)90900-0 · 1.90 Impact Factor
  • G. Velleaud · M. Mercier · J. Puvinel · G. Aubert · P. Escudier ·
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    ABSTRACT: After showing the existence of second order M.E. effect β, in Fe5LiO8 [1], we try to verify Lee and Rado's assumptions. These authors suppose that the existence of β is connected with the rotation of magnetic domains. We compare the magnetoelectric β and the magnetization σ curves vs the magnetic field H0. The latter curve reveals the different magnetic modes, and therefore illustrates the behavior of the magnetic domains. This comparison has been made for several directions of the applied field in order to illustrate all possible cases of rotation of the domains and allows us to confirm the basic assumption.
    Solid State Communications 08/1978; 27(7):729–733. DOI:10.1016/0038-1098(78)90013-3 · 1.90 Impact Factor
  • M. Mercier · G. Velleaud · J. Puvinel ·
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    ABSTRACT: Due to the crystal symmetry of the ordered phase of LiFe5O8, P4332 magnetoelectric effects of the first and second order (αβγ) are allowed for the magnetic punctual sub-groups related to the magnetization process. Second order effects are measured at 4.2 K for which value the electrical conductivity is low enough.
    Physica B+C 03/1977; s 86–88. DOI:10.1016/0378-4363(77)90803-8
  • G. Velleaud · M. Mercier ·
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    ABSTRACT: A first order magnetoelectric effect with α = 10-2 is measured on a powder sample of DyCoO3, due to the Dy3+ ions. The metamagnetic behaviour is demonstrated.
    Solid State Communications 07/1975; 17(2):237-239. DOI:10.1016/0038-1098(75)90051-4 · 1.90 Impact Factor
  • G. Velleaud · M. Mercier ·
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    ABSTRACT: The magnetoelectric effect of TbAlO3 near TN is studied within the Ising model approximation. With α/α0 = D(1 - T/TN)β we find D = 1.5 and β = 0.32. By applying a magnetic field along various directions, the magnetoelectric effect confirms the metamagnetic behaviour of TbAlO 3. L'interprétation de l'effet magnétoélectrique de TbAlO3 au voisinage de TN est faite à l'aide du modèle d'Ising. Avec α/α 0 = D(1 - T/TN)β, on obtient D = 1,5 et β = 0,32. Par application d'un champ magnétique suivant différentes directions cristallographiques, l'effet magnétoélectrique permet également de mettre en évidence le comportement métamagnétique de ce composé.
    Journal de Physique Lettres 01/1975; DOI:10.1051/jphyslet:019750036010025100