R. H. Kodama, Magnetic nanoparticles, Journal of Magnetism and Magnetic Materials, vol.200, issue.13, pp.359-372, 1999.

A. Lu, E. Salabas, and F. Schüth, Magnetic nanoparticles: Synthesis, protection, functionalization, and application, Angewandte Chemie International Edition, vol.46, issue.8, pp.1222-1244, 2007.

E. Tronc, D. Fiorani, M. Nogus, A. Testa, F. Lucari et al.,

W. Grenèche, N. Wernsdorfer, C. Galvez, D. Chanac, J. Mailly et al., Surface effects in noninteracting and interacting gamma-fe2o3 nanoparticles, Journal of Magnetism and Magnetic Materials, vol.262, issue.1, pp.6-14, 2003.

A. E. Berkowitz, J. A. Lahut, I. S. Jacobs, L. M. Levinson, and D. W. Forester, Spin Pinning at Ferrite-Organic Interfaces, Phys. Rev. Lett, vol.34, issue.10, pp.594-597, 1975.

Y. Kseolu, Effect of surfactant coating on magnetic properties of fe3o4 nanoparticles: {ESR} study, Journal of Magnetism and Magnetic Materials, vol.300, issue.1, pp.327-330, 2006.

F. Luis, J. Torres, L. Garcia, J. Bartolomé, J. Stankiewicz et al., Enhancement of the magnetic anisotropy of nanometer-sized Co clusters: Influence of the surface and of interparticle interactions, Physical Review B, vol.65, issue.9

P. Hajra, P. Brahma, S. Dutta, S. Banerjee, and D. Chakravorty, Enhancement of magnetic anisotropy in mechanically attrited Cr2o3 nanoparticles, Journal of Magnetism and Magnetic Materials, vol.324, issue.7, pp.1425-1430, 2012.

A. Kihal, G. Fillion, B. Bouzabata, and B. Barbara, High field surface magnetic study of Fe3o4 nanoparticles, physica status solidi (b), vol.249, issue.3, pp.604-614, 2012.

K. Nadeem, H. Krenn, T. Traussnig, R. Wurschum, D. V. Szaboi et al., Spin-glass freezing of maghemite nanoparticles prepared by microwave plasma synthesis, Journal of Applied Physics, vol.111, issue.11, p.113911, 2012.

E. Tronc, A. Ezzir, R. Cherkaoui, C. Chanac, M. Nogues et al., Surface-related properties of-Fe< sub> 2</sub> O< sub> 3</sub> nanoparticles, Journal of Magnetism and Magnetic Materials, vol.221, issue.1, pp.63-79, 2000.

D. A. Van-leeuwen, J. M. Van-ruitenbeek, L. J. De-jongh, A. Ceriotti, G. Pacchioni et al., Quenching of magnetic moments by ligand-metal interactions in nanosized magnetic metal clusters, Phys. Rev. Lett, vol.73, issue.10, pp.1432-1435, 1994.

J. Mazo-zuluaga, J. Restrepo, F. Munoz, and J. Mejia-lopez, Surface anisotropy, hysteretic, and magnetic properties of magnetite nanoparticles: A simulation study, Journal of Applied Physics, vol.105, issue.12, p.123907, 2009.

Q. Sun, B. V. , M. Marquez, P. Jena, C. Gonzalez et al., Theoretical study on gold-coated iron oxide nanostructure: Magnetism and bioselectivity for amino acids, The Journal of Physical Chemistry C, vol.111, pp.4159-4163, 2007.

P. Giannozzi, S. Baroni, N. Bonini, M. Calandra, R. Car et al., Quantum espresso: a modular and opensource software project for quantum simulations of materials, Journal of Physics: Condensed Matter, vol.21, issue.39, p.395502, 2009.
URL : https://hal.archives-ouvertes.fr/hal-00717147

J. P. Perdew, K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple, Phys. Rev. Lett, vol.77, pp.3865-3868, 1996.

A. D. Corso and A. M. Conte, Spin-orbit coupling with ultrasoft pseudopotentials: Application to au and pt, Phys. Rev. B, vol.71, p.115106, 2005.

Q. Wang, Q. Sun, M. Sakurai, J. Z. Yu, B. L. Gu et al., Geometry and electronic structure of magic iron oxide clusters, Phys. Rev. B, vol.59, pp.12672-12677, 1999.

S. Grazulis, A. Daskevic, A. Merkys, D. Chateigner, L. Lutterotti et al., Crystallography Open Database (COD): an open-access collection of crystal structures and platform for world-wide collaboration, Nucleic acids research, vol.40, issue.D1, pp.420-427, 2012.

S. R. Bahn and K. W. Jacobsen, An object-oriented scripting interface to a legacy electronic structure code, Comput. Sci. Eng, vol.4, issue.3, pp.56-66, 2002.

U. V. Barth and L. Hedin, A local exchange-correlation potential for the spin polarized case : I, Solid State Phys, vol.5, p.1629, 1972.

G. J. Martyna and M. E. Tuckerman, A reciprocal space based method for treating long range interactions in ab initio and force-field-based calculations in clusters, The Journal of Chemical Physics, vol.110, issue.6, pp.2810-2821, 1999.

M. Uhl and B. Siberchicot, A first-principles study of exchange integrals in magnetite, Journal of Physics: Condensed Matter, vol.7, issue.22, p.4227, 1995.

W. H. Press, B. P. Flannery, S. A. Teukolsky, and W. T. Vetterling, Numerical Recipes in Fortran 77: The Art of Scientific Computing, 1992.

B. Fongang, Y. Labaye, F. Calvayrac, S. Zekeng, and J. Grenèche, Coupled structural and magnetic properties of ferric fluoride nanostructures: Part II, a Monte Carlo-Heisenberg study, Journal of Magnetism and Magnetic Materials, vol.324, issue.22, pp.3646-3651, 2012.