References of "Goffinet, Marco"
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See detailLattice dynamics of multiferroic BiFeO3 studied by inelastic x-ray scattering
Borissenko, Elena; Goffinet, Marco ULg; Bosak, Alexei et al

in Journal of Physics : Condensed Matter (2013), 25

We report an experimental study of the phonon dispersion in BiFeO3 single crystals at ambient conditions by inelastic x-ray scattering (IXS). The phonon dispersions were recorded along several symmetry ... [more ▼]

We report an experimental study of the phonon dispersion in BiFeO3 single crystals at ambient conditions by inelastic x-ray scattering (IXS). The phonon dispersions were recorded along several symmetry directions up to 35 meV. Our results compare favorably with first-principles calculations performed using density functional theory (DFT) within the local-density approximation (LDA). We resolve a discrepancy concerning the symmetry of the optical phonon branches observed by Raman spectroscopy, determine the energy of the lowest Raman and infrared silent mode, and derive a subset of the elastic moduli of BiFeO3. [less ▲]

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See detailFirst-principles study of a pressure-induced spin transition in multiferroic Bi2FeCrO6
Goffinet, Marco ULg; Iniguez, Jorge; Ghosez, Philippe ULg

in Physical Review. B, Condensed Matter and Materials Physics (2012), 86

We report on a first-principles study of the structural, electronic, andmagnetic properties of multiferroic double perovskite Bi2FeCrO6, using density functional theory within the local spin-density ... [more ▼]

We report on a first-principles study of the structural, electronic, andmagnetic properties of multiferroic double perovskite Bi2FeCrO6, using density functional theory within the local spin-density approximation (LSDA), the LSDA+Uapproximation as well as a hybrid functional scheme.We showthat Bi2FeCrO6 presents two competing ferrimagnetic phases, sharing the same total magnetic moment of 2μB per unit cell but with a different electronic configuration for the Fe3+ species. The phase with high-spin iron is the ground state at ambient conditions, but we predict that low-spin iron gets stabilized under compression.We also investigate the corresponding ferromagnetic phases, and show that the magnetic couplings sharply decrease when moving form high- to low-spin Fe3+. [less ▲]

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See detailFirst-principles study of multiferroic materials : BiFeO3 and Bi2FeCrO6
Goffinet, Marco ULg

Doctoral thesis (2011)

The present work is devoted to an ab-initio characterization, using planewave and localized basis sets, of multiferroic and magnetoelectric materials. After a general description of the underlying ... [more ▼]

The present work is devoted to an ab-initio characterization, using planewave and localized basis sets, of multiferroic and magnetoelectric materials. After a general description of the underlying concepts and computational techniques, we focus on BiFeO3, which is probably the most intensively studied multiferroic. We start our investigation by comparing the ability of different exchange-correlation functionals (LSDA(+U), GGA and hybrid) to accurately describe the most fundamental properties of BiFeO3 (crystallographic structure, electronic band structure, magnetism, phonons at Gamma, Born effective charges). Next we present infrared reflectivity and Raman spectra obtained from first-principles and compare them to experimental data. We then extend the study of the dynamical properties of BiFeO3 to the whole Brillouin zone by analyzing the phonon band structure, density of states and interatomic force constants. We also use combined Einstein and Debye models to fit the specific heat as obtained from first-principles and compare it to experimental data. The final part of this thesis is devoted to the investigation of pressure driven spin phase transitions in Bi2FeCrO6 . [less ▲]

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See detailHybrid functional study of prototypical multiferroic bismuth ferrite
Goffinet, Marco ULg; Hermet, Patrick ULg; Bilc, Daniel ULg et al

in Physical Review. B, Condensed Matter and Materials Physics (2009), 79(1),

We report a systematic comparison of various exchange-correlation functionals for the prediction of the structural, magnetic, electronic, and dynamical (phonons and Born effective charge tensors ... [more ▼]

We report a systematic comparison of various exchange-correlation functionals for the prediction of the structural, magnetic, electronic, and dynamical (phonons and Born effective charge tensors) properties of bismuth ferrite, a prototypical multiferroic compound. We have not only considered the usual approximations to density-functional theory such as the local-density approximation (LDA), generalized (GGA), and LDA+U, but also hybrid approaches such as B3LYP and B1. The recent B1-WC hybrid functional of Bilc [Phys. Rev. B 77, 165107 (2008)], with the GGA functional of Wu and Cohen and an exact exchange mixing parameter of 0.16, provides very good overall agreement with experiments and can be considered as a valuable alternative to LDA, GGA, and DFT+U for the study of bismuth ferrite. This does not only allow a reliable interpretation of the physical properties of this specific compound but also opens perspectives for further and more predictive first-principles investigations of multiferroic materials. [less ▲]

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See detailComment on "Electronic structure and zone-center phonon modes in multiferroic bulk BiFeO3" [J. Appl. Phys. 103, 083712 (2008)]
Hermet, Patrick ULg; Goffinet, Marco ULg; Ghosez, Philippe ULg

in Journal of Applied Physics (2009), 105

In a recent paper, Tutuncu and Srivastava [J. Appl. Phys. 103, 083712 (2008)] report the electronic structure and the assignment of the zone-center phonon modes of the R3c phase of BiFeO3 using the ... [more ▼]

In a recent paper, Tutuncu and Srivastava [J. Appl. Phys. 103, 083712 (2008)] report the electronic structure and the assignment of the zone-center phonon modes of the R3c phase of BiFeO3 using the density functional theory. In the present comment, we point out some physical inaccuracies in their mode assignment. We review their interpretation and analyze which conclusions are actually justified. [less ▲]

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See detailRaman and infrared spectra of multiferroic bismuth ferrite from first principles
Hermet, Patrick ULg; Goffinet, Marco ULg; Kreisel, J. et al

in Physical Review. B, Condensed Matter and Materials Physics (2007), 75

The entire zone-center phonon spectrum of the R3c ferroelectric antiferromagnetic phase of bismuth ferrite is computed using a first-principles approach based on density functional theory. Two phonon ... [more ▼]

The entire zone-center phonon spectrum of the R3c ferroelectric antiferromagnetic phase of bismuth ferrite is computed using a first-principles approach based on density functional theory. Two phonon modes exhibiting eigendisplacement vectors that strongly overlap with the atomic distortions taking place at the ferroelectric structural phase transition are identified and give support to a transition with displacive character. Both Raman and infrared reflectivity spectra are also computed, providing benchmark theoretical results for the assignment of experimental spectra. [less ▲]

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