title: New approach for understanding experimental NMR relaxivity properties of magnetic nanoparticles: focus on cobalt ferrite.
abstract: Relaxivities r1and r2of cobalt ferrite magnetic nanoparticles (MNPs) have been investigated in the aim of improving the models of NMR relaxation induced by magnetic nanoparticles. On one hand a large set of relaxivity data has been collected for cobalt ferrite MNP dispersions. On the other hand the relaxivity has been calculated for dispersions of cobalt ferrite MNPs with size ranging from 5 to 13 nm, without using any fitting procedure. The model is based on the magnetic dipolar interaction between the magnetic moments of the MNPs and the1H nuclei. It takes into account both the longitudinal and transversal contributions of the magnetic moments of MNPs leading to three contributions in the relaxation equations. The comparison of the experimental and theoretical data shows a good agreement of the NMR profiles as well as the temperature dependence.
authors.affiliation: PHENIX, Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Physico-Chimie des Electrolytes et Nanosystème Interfaciaux (PHENIX) Paris, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Rollet
authors.affiliation: PHENIX, Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Physico-Chimie des Electrolytes et Nanosystème Interfaciaux (PHENIX) Paris, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Neveu
authors.affiliation: Laboratoire Interfaces, Confinement, Matériaux et Nanostructures - ICMN Interfaces, Confinement, Matériaux et Nanostructures - ICMN, CNRS, Université Orléans, Orléans, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Porion
authors.affiliation: PHENIX, Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Physico-Chimie des Electrolytes et Nanosystème Interfaciaux (PHENIX) Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Dupuis
authors.affiliation: PHENIX, Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Physico-Chimie des Electrolytes et Nanosystème Interfaciaux (PHENIX) Paris, France.
authors.forename: Nadine
authors.initials: N
authors.lastname: Cherrak
authors.affiliation: PHENIX, Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Physico-Chimie des Electrolytes et Nanosystème Interfaciaux (PHENIX) Paris, France and Physique de la Matière condensée (PMC), CNRS, Ecole Polytechnique, Palaiseau, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Levitz