Structure and Magnetic Proporties of Polymer Matrix Nanocomposites

Structure and magnetic properties of the thermal decomposition products of Fe(III)Co(II) acrylate complex were analysed. The crystalline phases, which were found in the fully processed material, at 643 K, were Fe$\text{}_{3}$O$\text{}_{4}$, CoFe$\text{}_{2}$O$\text{}_{4}$, and CoO and had a mean particle size of about 30 nm. In the intermediate stages of the thermolysis iron was present in a form of Fe$\text{}^{III}$ (trivalent low-spin iron), Fe$\text{}^{2+}$ (divalent high-spin iron), and Fe$\text{}_{3}$O$\text{}_{4}$. The coercivity and remanence were measured versus temperature in the range of 5-300 K, in 1.1 T applied field. Both, $\text{}_{M}$H$\text{}_{c}$ and M$\text{}_{r}$, decreased showing room temperature values of 0.038 T and 7.49 mT, for coercivity and remanence, respectively. At temperatures below 200 K the hysteresis loops were asymmetrical, opened and shifted towards negative field values.