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

• We investigate the structural and magnetic properties, as well as the heat release, of an iron/wüstite composite.
• The samples are produced using high energy mechanical milling.
• Fe nanoparticles embedded in a wüstite matrix have high stability in time.
• When an alternating magnetic field is applied, the sample temperature increases up to ∼46°C.
• The composite is an interesting candidate for biomedical applications, such as magnetic hyperthermia agent for cancer therapy.

We 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.