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Relating Magnetic Properties and High Hyperthermia Performance of Iron Oxide Nanoflowers

Abstract: 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.

Otras publicaciones de la misma revista o congreso con autores/as de la Universidad de Cantabria

 Autoría: Bender P., Fock J., Frandsen C., Hansen M., Balceris C., Ludwig F., Posth O., Wetterskog E., Bogart L., Southern P., Szczerba W., Zeng L., Witte K., Grüttner C., Westphal F., Honecker D., González-Alonso D., Fernández Barquín L., Johansson C.,

 Fuente: J. Phys. Chem. C 2018, 122, 5, 3068-3077

Editorial: American Chemical Society

 Año de publicación: 2018

Nº de páginas: 10

Tipo de publicación: Artículo de Revista

 DOI: 10.1021/acs.jpcc.7b11255

ISSN: 1932-7447,1932-7455

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

Url de la publicación: https://doi.org/10.1021/acs.jpcc.7b11255

Autores/as

PHILIPP FLORIAN BENDER

FOCK, JEPPE

FRANDSEN, CATHERINE

HANSEN, MIKKEL F.

BALCERIS, CHRISTOPH

LUDWIG, FRANK

POSTH, OLIVER

WETTERSKOG, ERIK

BOGART, LARA K.

SOUTHERN, PAUL

SZCZERBA, WOJCIECH

ZENG, LUNJIE

WITTE, KERSTIN

GRÜTTNER, CORDULA

WESTPHAL, FRITZ

HONECKER, DIRK

DAVID GONZALEZ ALONSO

JOHANSSON, CHRISTER