Influence of clustering on the magnetic properties and hyperthermia performance of iron oxide nanoparticles
Artikel i vetenskaplig tidskrift, 2018
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™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™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 105rad 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 (FS-L, XL, XXL) excel in magnetic hyperthermia experiments.
core-clusters
magnetic nanoparticles
numerical inversion
multi-core particles
magnetic hyperthermia
nanoflowers
Författare
P. Bender
Université du Luxembourg
Universidad de Cantabria
J. Fock
Danmarks Tekniske Universitet (DTU)
M. F. Hansen
Danmarks Tekniske Universitet (DTU)
Lara K. Bogart
University College London (UCL)
P. Southern
University College London (UCL)
Frank Ludwig
Technische Universität Braunschweig
F. Wiekhorst
Physikalisch-Technische Bundesanstalt (PTB)
W. Szczerba
Bundesanstalt für Materialforschung und -prüfung (BAM)
Akademia Gorniczo-Hutnicza im. Stanislawa Staszica w Krakowie
Lunjie Zeng
Chalmers, Fysik, Eva Olsson Group
D. Heinke
Nanopet Pharma
N. Gehrke
Nanopet Pharma
M. T.Fernández Díaz
Institut Laue-Langevin
D. Gonzalez-Alonso
Universidad de Cantabria
J. I. Espeso
Universidad de Cantabria
J. Rodríguez Fernández
Universidad de Cantabria
C. Johansson
RISE Research Institutes of Sweden
Nanotechnology
0957-4484 (ISSN) 1361-6528 (eISSN)
Vol. 29 42 425705Ämneskategorier
Oorganisk kemi
Annan fysik
Den kondenserade materiens fysik
Infrastruktur
Chalmers materialanalyslaboratorium
DOI
10.1088/1361-6528/aad67d