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Influence of clustering on the magnetic properties and hyperthermia performance of iron oxide nanoparticles

Abstract: Clustering of magnetic nanoparticles can drastically change their collective magnetic properties, which in turn may influence their performance in technological or biomedical applications. Here, we investigate a commercial colloidal dispersion (FeraSpin (TM) R), which contains dense clusters of iron oxide cores (mean size around 9 nm according to neutron diffraction) with varying cluster size (about 18-56 nm according to small angle x-ray diffraction), and its individual size fractions (FeraSpin (TM) XS, S, M, L, XL, XXL). The magnetic properties of the colloids were characterized by isothermal magnetization, as well as frequency-dependent optomagnetic and AC susceptibility measurements. From these measurements we derive the underlying moment and relaxation frequency distributions, respectively. Analysis of the distributions shows that the clustering of the initially superparamagnetic cores leads to remanent magnetic moments within the large clusters. At frequencies below 10(5) rad s(-1), the relaxation of the clusters is dominated by Brownian (rotation) relaxation. At higher frequencies, where Brownian relaxation is inhibited due to viscous friction, the clusters still show an appreciable magnetic relaxation due to internal moment relaxation within the clusters. As a result of the internal moment relaxation, the colloids with the large clusters (FSL, XL, XXL) excel in magnetic hyperthermia experiments.

 Fuente: Nanotechnology, 2018, Vol. 29, Iss. 42, Art. Num. 425705

Editorial: IOP Publishing

 Fecha de publicación: 15/08/2018

Nº de páginas: 13

Tipo de publicación: Artículo de Revista

DOI: 10.1088/1361-6528/aad67d

ISSN: 0957-4484,1361-6528

Proyecto europeo: info:eu-repo/grantAgreement/EC/FP7/604448/EU/Nanometrology Standardization Methods for Magnetic Nanoparticles/NanoMag/

Url de la publicación: https://doi.org/10.1088/1361-6528/aad67d

Autores/as

PHILIPP FLORIAN BENDER

FOCK, JEPPE

HANSEN, MIKKEL FOUGT

BOGART, LARA KATRINA

SOUTHERN, PAUL

LUDWIG, FRANK

WIEKHORST, FRANK

SZCZERBA, WOJCIECH

ZENG, LUNJIE

HEINKE, DAVID

GEHRKE, NICOLE

FERNÁNDEZ DÍAZ, M. T.

DAVID GONZALEZ ALONSO

JOHANSSON, CHRISTER I.