Interparticle interaction effect on magnetization dynamics of multicore iron oxide particles in alternating magnetic field

Abstract

Magnetic multicore iron oxide particles are nowadays intensively studied for application in magnetic hyperthermia. These particles compose of superparamagnetic iron oxide cores densely packed due to magnetic interactions. The magnetic interaction leads to the increase of energy barrier of magnetization reversal and therefore the heating losses in alternating magnetic field can be enhanced. However, the magnetization dynamics of such systems in alternating magnetic field remains still unclear. Apparently, the main parameters influencing the interaction with magnetic field are the morphology of single cores and multicore particles as well as the intercore and interparticle magnetic interactions. In the current work, we investigate the effect of interparticle interactions between the multicore particles on the heating efficiency of magnetic dispersions in alternating magnetic field. Two types of multicore particles were prepared: naked multicore particles displaying dipole-dipole interactions and multicore particles with surface coating preventing the interaction of multicores. Both types of multicore particles were composed of 13 nm iron oxide cores and have the hydrodynamic size of about 85 nm. To study the absorption of AMF energy, multicore particles were dispersed in media with different viscosity (water and agarose). It was demonstrated that covered multicore particles display significantly higher heating efficiency in both media than naked particles, which is associated with the elimination of dipole-dipole interaction between multicores.