Mechano-synthesis, structural and magnetic characterization, and heat release of α-Fe nanoparticles embedded in a wüstite matrix

Abstract

a b s t r a c tWe report a study of the structural and magnetic properties, as well as of the heat release, of an iron/ wüstite composite, prepared from iron powder and water by high energy mechanical milling. We identify that the produced sample consists of α-Fe nanoparticles embedded in a wüstite matrix and has high stability in time. Moreover, we observe that it presents noticeable features, as exchange bias effect at low temperatures and, when an alternating magnetic field is applied, its temperature reaches ∼46°C in ∼600 s. Thus, the results and the possibility of tuning the magnetic properties of α-Fe nanoparticles embedded in a wüstite matrix, through interface interactions, place this system as a very attractive candidate for biomedical applications such as magnetic hyperthermia agent for cancer therapy.

Magnetic nanoparticles hyperthermia in a non-adiabatic and radiating process

“…We start presenting the well-known adiabatic model for magnetic hyperthermia 2 , 4 , 12 , 14 – 18 , with its assumptions and limitations.…”

“…( 2 ) mimicking a system in an adiabatic and isochoric process, SLP may be expressed as Remarkably, Eq. ( 4 ) has been addressed and employed in numerous works found in literature 2 , 4 , 12 , 14 – 18 . However, it is worth pointing out that this first approach to estimate SLP has validity only in the quasi-adiabatic regime, i.e.…”

“…From this measurement, SLP is commonly quantified by standard calorimetric methods in which a quasi-adiabatic regime is assumed, i.e. the nanoparticles or the ferrofluid behave as a quasi-adiabatic system whose energy is absorbed by the magnetic material at a constant rate 2 , 4 , 12 , 14 – 18 . Within this picture, just the slope of the temperature curve during a short time interval after applying AMF is analysed.…”

Specific loss power of magnetic nanoparticles (fluid) hyperthermia in non-adiabatic conditions

“…Mimicking an adiabatic system. We start our approach to magnetic hyperthermia by presenting the well-known adiabatic model 2,4,6,[8][9][10][11][12] , with its assumptions and limitations.…”

“…From this measurement, SLP is commonly quantified by standard calorimetric methods in which a quasi-adiabatic regime is assumed, i.e. the nanoparticles or the ferrofluid behave as a quasi-adiabatic system whose energy is absorbed by the magnetic material at a constant rate 2,4,6,[8][9][10][11][12] . Within this picture, just the slope of the temperature curve during a short time interval after applying AMF is analyzed.…”