No abstract

Two series of nanosized cobalt spinel ferrites CoFe2O4 are synthesized from metal salts using high-energy ball milling with the addition of NaCl as a growth agent (series CFO-NaCl), and without (CFO Series). The particle properties are characterized using atomic force microscopy, as well as magnetic and calorimetric measurements. It is shown that the average sizes of the nanoparticles were ∼5.6 and ∼10.3 nm for CFO and CFO-NaCl series, respectively. We performed magnetostatic measurements and determined the parameters that are required to analyze the magnetic state and remagnetization processes of the nanoparticles. It is shown that the blocking temperature is ≈160 K for CFO samples and ≈300 K for the CFO-NaCl series. It was concluded that at 293 K the CFO series particles exhibit a superparamagnetic state, whereas the CFO-NaCl series are in the blocked state. The specific loss power that is scattered by the synthesized nanoparticle ensembles placed in an alternating magnetic field, is measured experimentally and theoretically assessed. The nature of the processes that determine the thermal characteristics of the nanoparticles is analyzed.

CoFe2O4/polypyrrole composite nanoparticles were synthesized using a high energy ball mill. Mössbauer and Fourier transform infrared spectroscopies, magnetization measurements and transmission electron microscopy were used for the characterization of samples. Specific loss power (SLP) was determined by exposing nanoparticles to an alternating magnetic field. Some changes in coercivity were observed and explained comparing CoFe2O4 nanoparticles withCoFe2O4/polypyrrole composite nanoparticles.

No abstract