I. Torres-díaz and C. Rinaldi, Recent progress in ferrofluids research: novel applications of magnetically controllable and tunable fluids, Soft Matter, vol.3, issue.276, pp.8584-8602, 2014.
DOI : 10.1038/ncomms1798

H. Shokrollahi, A. Khorramdin, and G. Isapour, Magnetic resonance imaging by using nano-magnetic particles, Journal of Magnetism and Magnetic Materials, vol.369, pp.176-183, 2014.
DOI : 10.1016/j.jmmm.2014.06.023

E. A. Périgo, G. Hemery, O. Sandre, D. Ortega, E. Garaio et al., Fundamentals and advances in magnetic hyperthermia, Applied Physics Reviews, vol.85, issue.4, p.41302, 2015.
DOI : 10.1118/1.3106342

H. Amata, F. Royer, F. Choueikani, D. Jamon, F. Parsy et al., Hybrid magneto-optical mode converter made with a magnetic nanoparticles
DOI : 10.1063/1.3671180
URL : https://hal.archives-ouvertes.fr/ujm-00692054

Y. Zou, K. Liu, Z. Shen, and X. Chen, Magnetic-fluid core optical fiber, Microfluid. Nanofluid, pp.447-451, 2011.
DOI : 10.1007/s10404-010-0665-5

H. E. Horng, C. S. Chen, K. L. Fang, S. Y. Yang, J. J. Chieh et al., Tunable optical switch using magnetic fluids, Applied Physics Letters, vol.1, issue.23, pp.85-5592, 2004.
DOI : 10.1063/1.1410331

D. S. Mathew and R. Juang, An overview of the structure and magnetism of spinel ferrite nanoparticles and their synthesis in microemulsions, Chemical Engineering Journal, vol.129, issue.1-3, pp.51-65, 2007.
DOI : 10.1016/j.cej.2006.11.001

N. A. Frey, S. Peng, K. Cheng, and S. Sun, Magnetic nanoparticles: synthesis, functionalization, and applications in bioimaging and magnetic energy storage, Chemical Society Reviews, vol.91, issue.291, pp.38-2532, 2009.
DOI : 10.1557/mrs2001.254

A. J. Rondinone, A. C. Samia, and Z. J. Zhang, Characterizing the magnetic anisotropy constant of spinel cobalt ferrite nanoparticles, Applied Physics Letters, vol.5, issue.24, pp.76-3624, 2000.
DOI : 10.1016/0304-8853(83)90470-5

S. Lefebure, E. Dubois, V. Cabuil, S. Neveu, and R. Massart, Monodisperse magnetic nanoparticles: Preparation and dispersion in water and oils, Journal of Materials Research, vol.84, issue.10, pp.2975-2981, 1998.
DOI : 10.1109/TMAG.1978.1059918
URL : https://hal.archives-ouvertes.fr/hal-00170358

D. Caruntu, G. Caruntu, Y. Chen, C. J. O-'connor, G. Goloverda et al., Synthesis of variable-sized nanocrystals of Fe 3 O 4 with high surface reactivity, Chem. Mater, pp.16-5527, 2004.

A. Abou-hassan, S. Neveu, V. Dupuis, and V. , Synthesis of cobalt ferrite nanoparticles in continuous-flow microreactors, RSC Advances, vol.126, issue.314, pp.11263-11266, 2012.
DOI : 10.1021/ja049931r

T. Hyeon, S. S. Lee, J. Park, Y. Chung, and H. B. Na, Synthesis of Highly Crystalline and Monodisperse Maghemite Nanocrystallites without a Size-Selection Process, Journal of the American Chemical Society, vol.123, issue.51, pp.123-12798, 2001.
DOI : 10.1021/ja016812s

L. Pérez-mirabet, E. Solano, F. Martínez-julián, R. Guzmán, J. Arbiol et al., One-pot synthesis of stable colloidal solutions of MFe ? 2 O 4 nanoparticles using oleylamine as solvent and stabilizer, Mater. Res. Bull, pp.48-966, 2013.

R. Massart, Preparation of aqueous magnetic liquids in alkaline and acidic media, IEEE Transactions on Magnetics, vol.17, issue.2, pp.1247-1248, 1981.
DOI : 10.1109/TMAG.1981.1061188

Y. Zhang, Z. Yang, D. Yin, Y. Liu, C. Fei et al., Composition and magnetic properties of cobalt ferrite nano-particles prepared by the co-precipitation method, Journal of Magnetism and Magnetic Materials, vol.322, issue.21, pp.322-3470, 2010.
DOI : 10.1016/j.jmmm.2010.06.047

R. J. Hill, J. R. Craig, and G. V. Gibbs, Systematics of the spinel structure type, Systematics of the spinel structure type, pp.317-339, 1979.
DOI : 10.1007/BF00307535

D. Peddis, C. Cannas, G. Piccaluga, E. Agostinelli, D. Fiorani et al., Spin-glass-like freezing and enhanced magnetization in ultra-small CoFe ? 2 O ? 4 nanoparticles, Cationic distribution and spin canting in CoFe ? 2 O ? 4 nanoparticles, p.426004, 2010.

G. A. Sawatzky, F. V. Woude, and A. H. Morrish, Cation Distributions in Octahedral and Tetrahedral Sites of the Ferrimagnetic Spinel CoFe ? 2 O 4, J. Appl. Phys, pp.39-1204, 1968.

G. A. Sawatzky, F. Van-der-woude, and A. H. Morrish, M??ssbauer Study of Several Ferrimagnetic Spinels, Physical Review, vol.19, issue.2, pp.747-757, 1969.
DOI : 10.1143/JPSJ.19.1182

P. J. Murray and J. , M??ssbauer studies in the spinel system coxfe3???xo4, Journal of Physics and Chemistry of Solids, vol.37, issue.6, pp.619-624, 1976.
DOI : 10.1016/0022-3697(76)90111-6

D. Peddis, C. Cannas, A. Musinu, A. Ardu, F. Orrù et al., Nanoparticle Arrangements on Magnetic Properties, Chemistry of Materials, vol.25, issue.10, pp.25-2005, 2013.
DOI : 10.1021/cm303352r

D. Carta, A. Corrias, A. Falqui, R. Brescia, E. Fantechi et al., EDS, HRTEM/STEM, and X-ray Absorption Spectroscopy Studies of Co-Substituted Maghemite Nanoparticles, The Journal of Physical Chemistry C, vol.117, issue.18, pp.9496-9506, 2013.
DOI : 10.1021/jp401706c

M. Artus, L. B. Tahar, F. Herbst, L. Smiri, F. Villain et al., Size-dependent magnetic properties of CoFe ? 2 O ? 4 nanoparticles prepared in polyol, J. Phys.: Condens. Matter, vol.23, issue.506001, 2011.

S. Li, V. T. John, C. O-'connor, V. Harris, and E. Carpenter, Cobalt-ferrite nanoparticles: Structure, cation distributions, and magnetic properties, Journal of Applied Physics, vol.87, issue.9, pp.6223-6225, 2000.
DOI : 10.1063/1.369115

J. F. Hochepied, P. Sainctavit, and M. P. Pileni, X-ray absorption spectra and X-ray magnetic circular dichroism studies at Fe and Co L 2,3 edges of mixed cobalt?zinc ferrite nanoparticles: cationic repartition, magnetic structure and hysteresis cycles, J. Magn. Magn. Mater, pp.231-315, 2001.

N. Kita, N. Shibuichi, and S. Sasaki, X-ray magnetic circular dichroism in cobalt???iron spinels and electronic states of Co ions, Journal of Synchrotron Radiation, vol.8, issue.2, pp.446-448, 2001.
DOI : 10.1107/S0909049500018409

D. Carta, G. Mountjoy, G. Navarra, M. F. Casula, D. Loche et al., X-ray Absorption Investigation of the Formation of Cobalt Ferrite Nanoparticles in an Aerogel Silica Matrix, The Journal of Physical Chemistry C, vol.111, issue.17, pp.6308-6317, 2007.
DOI : 10.1021/jp0708805

C. M. Henderson, J. M. Charnock, and D. A. Plant, Cation occupancies in Mg, Co, Ni, Zn, Al ferrite spinels: a multi-element EXAFS study, Journal of Physics: Condensed Matter, vol.19, issue.7, p.76214, 2007.
DOI : 10.1088/0953-8984/19/7/076214

S. Staniland, W. Williams, N. Telling, G. Van-der-laan, A. Harrison et al., Controlled cobalt doping of magnetosomes in vivo, Nature Nanotechnology, vol.67, issue.3, pp.158-162, 2008.
DOI : 10.2138/am-1998-11-1228

V. S. Coker, C. I. Pearce, R. A. Pattrick, G. Van-der-laan, N. D. Telling et al., Probing the site occupancies of Co-, Ni-, and Mn-substituted biogenic magnetite using XAS and XMCD, American Mineralogist, vol.93, issue.7, pp.93-1119, 2008.
DOI : 10.2138/am.2008.2681

V. S. Coker, N. D. Telling, G. Van-der-laan, R. A. Pattrick, C. I. Pearce et al., Harnessing the Extracellular Bacterial Production of Nanoscale Cobalt Ferrite with Exploitable Magnetic Properties, ACS Nano, vol.3, issue.7, pp.1922-1928, 2009.
DOI : 10.1021/nn900293d

G. Subías, V. Cuartero, J. García, J. Blasco, S. Lafuerza et al., spinels, Physical Review B, vol.7, issue.9, p.94408, 2013.
DOI : 10.1063/1.3650251

D. K. Kim and J. Dobson, Nanomedicine for targeted drug delivery, Journal of Materials Chemistry, vol.24, issue.35, pp.6294-6307, 2009.
DOI : 10.1016/0016-5085(93)90271-D

S. Gyergyek, D. Makovec, A. Kodre, I. Ar?on, M. Jagodi? et al., Influence of synthesis method on structural and magnetic properties of cobalt ferrite nanoparticles, Journal of Nanoparticle Research, vol.58, issue.346, pp.12-1263, 2009.
DOI : 10.3181/00379727-158-40158

G. Aquilanti, A. Cognigni, and M. , Cation Distribution in??Zn Doped Cobalt Nanoferrites Determined by X-ray Absorption Spectroscopy, Journal of Superconductivity and Novel Magnetism, vol.58, issue.209, pp.659-663, 2010.
DOI : 10.1103/PhysRevB.58.7565

C. Schmitz-antoniak, D. Schmitz, P. Borisov, F. M. De-groot, S. Stienen et al., Electric in-plane polarization in multiferroic CoFe2O4, Nat Commun, vol.4, 2013.

K. O. Abdulwahab, M. A. Malik, P. O-'brien, G. A. Timco, F. Tuna et al., A One-Pot Synthesis of Monodispersed Iron Cobalt Oxide and Iron Manganese Oxide Nanoparticles from Bimetallic Pivalate Clusters, Chemistry of Materials, vol.26, issue.2, pp.999-1013, 2014.
DOI : 10.1021/cm403047v

C. I. Pearce, C. M. Henderson, R. A. Pattrick, G. V. Laan, and D. J. Vaughan, Direct determination of cation site occupancies in natural ferrite spinels by L2,3 X-ray absorption spectroscopy and X-ray magnetic circular dichroism, American Mineralogist, vol.91, issue.5-6, pp.91-880, 2015.
DOI : 10.2138/am.2006.2048

D. Erdem, N. S. Bingham, F. J. Heiligtag, N. Pilet, P. Warnicke et al., CoFe ? 2 O ? 4 and CoFe ? 2 O 4 -SiO ? 2 nanoparticle thin films with perpendicular magnetic anisotropy for magnetic and magneto-optical applications, Adv. Funct. Mater, pp.26-1954, 2016.

F. A. Tourinho, R. Franck, and R. Massart, Aqueous ferrofluids based on manganese and cobalt ferrites, Journal of Materials Science, vol.5, issue.7, pp.25-3249, 1990.
DOI : 10.1007/BF00587682

Y. I. Kim, D. Kim, and C. S. Lee, Synthesis and characterization of CoFe2O4 magnetic nanoparticles prepared by temperature-controlled coprecipitation method, Physica B: Condensed Matter, vol.337, issue.1-4, pp.42-51, 2003.
DOI : 10.1016/S0921-4526(03)00322-3

M. A. Soler, E. C. Lima, S. W. Da-silva, T. F. Melo, A. C. Pimenta et al., Aging Investigation of Cobalt Ferrite Nanoparticles in Low pH Magnetic Fluid, Langmuir, vol.23, issue.19, pp.9611-9617, 2007.
DOI : 10.1021/la701358g

F. Tourinho, R. Franck, R. Massart, and R. Perzynski, Synthesis and magnetic properties of managanese and cobalt ferrite ferrofluids, Prog. Colloid Polym. Sci, pp.79-128, 1989.

A. Bee, R. Massart, and S. Neveu, Synthesis of very fine maghemite particles, Journal of Magnetism and Magnetic Materials, vol.149, issue.1-2, pp.6-9, 1995.
DOI : 10.1016/0304-8853(95)00317-7
URL : https://hal.archives-ouvertes.fr/hal-00172906

T. J. Daou, G. Pourroy, S. Bégin-colin, J. M. Grenèche, C. Ulhaq-bouillet et al., Hydrothermal Synthesis of Monodisperse Magnetite Nanoparticles, Chemistry of Materials, vol.18, issue.18, pp.4399-4404, 2006.
DOI : 10.1021/cm060805r
URL : https://hal.archives-ouvertes.fr/hal-00206075

V. Cabuil, V. Dupuis, D. Talbot, and S. Neveu, Ionic magnetic fluid based on cobalt ferrite nanoparticles: Influence of hydrothermal treatment on the nanoparticle size, Journal of Magnetism and Magnetic Materials, vol.323, issue.10, pp.323-1238, 2011.
DOI : 10.1016/j.jmmm.2010.11.013

J. D. Gomes, M. H. Sousa, F. A. Tourinho, R. Aquino, G. J. Da-silva et al., Synthesis of Core???Shell Ferrite Nanoparticles for Ferrofluids:??? Chemical and Magnetic Analysis, The Journal of Physical Chemistry C, vol.112, issue.16, pp.6220-6227, 2008.
DOI : 10.1021/jp7097608
URL : https://hal.archives-ouvertes.fr/hal-00347810

P. Scherrer, Bestimmung der Gröe und der inneren Struktur von Kolloidteilchen mittels Röntgenstrahlen, Göttinger Nachrichten Math. Phys, vol.2, pp.98-100, 1918.
DOI : 10.1007/978-3-662-33915-2_7

U. Holzwarth and N. Gibson, The Scherrer equation versus the 'Debye-Scherrer equation', Nature Nanotechnology, vol.64, issue.9, pp.534-534, 2011.
DOI : 10.1107/S0021889878012844

P. Ohresser, E. Otero, F. Choueikani, K. Chen, S. Stanescu et al., DEIMOS: A beamline dedicated to dichroism measurements in the 350???2500 eV energy range, Review of Scientific Instruments, vol.85, issue.1, p.13106, 2014.
DOI : 10.1088/1742-6596/425/7/072022
URL : https://hal.archives-ouvertes.fr/hal-01088125

S. Brice-profeta, M. A. Arrio, E. Tronc, N. Menguy, I. Letard et al., Magnetic order in - nanoparticles: a XMCD study, Journal of Magnetism and Magnetic Materials, vol.288, pp.288-354, 2005.
DOI : 10.1016/j.jmmm.2004.09.120
URL : https://hal.archives-ouvertes.fr/hal-00112611

C. Carvallo, P. Sainctavit, M. Arrio, N. Menguy, Y. Wang et al., Biogenic vs. abiogenic magnetite nanoparticles: A XMCD study, American Mineralogist, vol.93, issue.5-6, pp.93-880, 2008.
DOI : 10.2138/am.2008.2713
URL : https://hal.archives-ouvertes.fr/hal-00325482

J. C. Slonczewski, Origin of Magnetic Anisotropy in Cobalt-Substituted Magnetite, Physical Review, vol.107, issue.6, pp.1341-1348, 1958.
DOI : 10.1103/PhysRev.107.1246

G. Van-der-laan, E. Arenholz, R. V. Chopdekar, and Y. Suzuki, Influence of crystal field on anisotropic x-ray magnetic linear dichroism at

M. Tachiki, Origin of the Magnetic Anisotropy Energy of Cobalt Ferrite, Progress of Theoretical Physics, vol.23, issue.6, pp.1055-1072, 1960.
DOI : 10.1143/PTP.23.1055

J. M. Coey, Noncollinear Spin Arrangement in Ultrafine Ferrimagnetic Crystallites, Physical Review Letters, vol.17, issue.17, pp.1140-1142, 1971.
DOI : 10.1139/p70-356
URL : http://www.tara.tcd.ie/bitstream/2262/31615/1/Noncollinear.pdf

E. Tronc, D. Fiorani, M. Noguès, A. M. Testa, F. Lucari et al., Surface effects in noninteracting and interacting ?-Fe ? 2 O 3 nanoparticles, J. Magn. Magn. Mater, pp.262-268, 2003.

C. Vazquez-vazquez, M. A. Lopez-quintela, M. C. Bujan-nunez, and J. Rivas, Finite size and surface effects on the magnetic properties of cobalt ferrite nanoparticles, Journal of Nanoparticle Research, vol.181, issue.245, pp.13-1663, 2011.
DOI : 10.1016/j.jssc.2007.10.034