Magnetic Hyperthermia With Fe $_{3}$ O $_{4}$ Nanoparticles: The Influence of Particle Size on Energy

We have studied the magnetic and power absorption properties of a series of magnetic nanoparticles (MNPs) of Fe₃O₄ with average sizes langdrang ranging from 3 to 26 nm. Heating experiments as a function of particle size revealed a strong increase in the specific power absorption (SPA) values for particles with langdrang = 25-30 nm. On the other side saturation magnetization M_S values of these MNPs remain essentially constant for particles with langdrang above 10 nm, suggesting that the absorption mechanism is not determined by M_S. The largest SPA value obtained was 130 W/g, corresponding to a bimodal particle distribution with average size values of 17 and 26 nm.