No abstract

The Fe‐MgO core‐shell morphology is proposed within the single‐domain nanoparticle regime as an enhanced magnetically driven hyperthermia carrier. The combinatory use of metallic iron as a core material together with the increased particle size (37–65 nm) triggers the tuning of dipolar interactions between particles and allows for further enhancement of their collective heating efficiency via concentration control. A theoretical universal estimation of hysteresis losses reveals the role of dipolar interactions on heating efficiency and outlines the strong influence of coupling effects on hyperthermia opening a novel roadmap towards multifunctional heat‐triggered theranostics particles.

The magnetic properties of γ-Fe2O3 nanoparticles synthesized by vaporization condensation in a solar image furnace have been studied using both magnetic measurements and Mössbauer spectroscopy. The mean size of the particles turns out to be easily controlled by changing the pressure conditions in the growth chamber. The particles exhibit superparamagnetic behavior at room temperature. Magnetic measurements show the appearance of magnetic hysteresis in the low-temperature range and from the evolution with temperature of the ferromagnetic ratio, MR/MS, we have determined the distribution of the blocking temperatures for the smallest particles that is fitted to a log-normal distribution leading to a mean blocking temperature 〈TB〉=38±15 K. The size distribution of the magnetic unit is also determined from this fitting, as well as from the Mössbauer spectra, obtaining a mean particle volume of about 3.5×105 Å3.