Relating Magnetic Properties and High Hyperthermia Performance of Iron Oxide Nanoflowers
Artikel i vetenskaplig tidskrift, 2018

We investigated, in depth, the interrelations among structure, magnetic properties, relaxation dynamics and magnetic hyperthermia performance of magnetic nanoflowers. The nanoflowers are about 39 nm in size, and consist of densely packed iron oxide cores. They display a remanent magnetization, which we explain by the exchange coupling between the cores, but we observe indications for internal spin disorder. By polarized small-angle neutron scattering, we unambiguously confirm that, on average, the nanoflowers are preferentially magnetized along one direction. The extracted discrete relaxation time distribution of the colloidally dispersed particles indicates the presence of three distinct relaxation contributions. We can explain the two slower processes by Brownian and classical Néel relaxation, respectively. The additionally observed very fast relaxation contributions are attributed by us to the relaxation of disordered spins within the nanoflowers. Finally, we show that the intrinsic loss power (ILP, magnetic hyperthermia performance) of the nanoflowers measured in colloidal dispersion at high frequency is comparatively large and independent of the viscosity of the surrounding medium. This concurs with our assumption that the observed relaxation in the high frequency range is primarily a result of internal spin relaxation, and possibly connected to the disordered spins within the individual nanoflowers.

Författare

P. Bender

Universidad de Cantabria

J. Fock

Danmarks Tekniske Universitet (DTU)

C. Frandsen

Danmarks Tekniske Universitet (DTU)

M. F. Hansen

Danmarks Tekniske Universitet (DTU)

Christoph Balceris

Technische Universität Braunschweig

Frank Ludwig

Technische Universität Braunschweig

Oliver Posth

Physikalisch-Technische Bundesanstalt (PTB)

E. Wetterskog

Uppsala universitet

Lara K. Bogart

University College London (UCL)

P. Southern

University College London (UCL)

W. Szczerba

Bundesanstalt für Materialforschung und -prüfung (BAM)

Akademia Gorniczo-Hutnicza im. Stanislawa Staszica w Krakowie

Lunjie Zeng

Chalmers, Fysik, Eva Olsson Group

Kerstin Witte

Micromod Partikeltechnologie

Universität Rostock

C. Gruettner

Micromod Partikeltechnologie

F. Westphal

Micromod Partikeltechnologie

Dirk Honecker

Institut Laue-Langevin

D. Gonzalez-Alonso

Universidad de Cantabria

L. F. Barquin

Universidad de Cantabria

Christer Johansson

RISE Acreo

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 122 5 3068-3077

Ämneskategorier

Annan fysik

Fusion, plasma och rymdfysik

Den kondenserade materiens fysik

DOI

10.1021/acs.jpcc.7b11255

Mer information

Senast uppdaterat

2018-02-28