부산대학교 도서관

Nanoparticles of $$\hbox {Ni}_{0.5}\hbox {Zn}_{0.5}\hbox {Fe}_{2}\hbox {O}_{4}$$ have been prepared by the co-precipitation method, and X-ray diffraction analysis has confirmed the formation of the desired ferrite. A pure epoxy sample and three samples of $$\hbox {epoxy/Ni}_{0.5}\hbox {Zn}_{0.5}\hbox {Fe}_{2}\hbox {O}_{4}$$ composites have also been prepared with different ferrite percentages. These samples have been characterized by Fourier transform infrared spectroscopy. The magnetization of the composites has been investigated by using a vibrating sample magnetometer and has revealed that these composites may be promising candidates for electromagnetic interference suppression. Moreover, the thermal diffusivity and thermal effusivity of epoxy and composite samples have been measured by using the photoacoustic technique, where a high enhancement of the thermal diffusivity with increasing ferrite content has been observed which can be attributed to the higher number of phonon vibrational modes as well as the longer mean free path of the ferrite nanoparticles due to their crystalline structure as compared to the amorphous structure of epoxy. Moreover, the formation of a percolated network of NiZn ferrite nanoparticles inside the epoxy may enhance the phonon conduction, increasing the value of the thermal diffusivity in the bulk of the samples. On the other hand, the almost constant values of the thermal effusivity-which is a surface property-suggest that these composites may be used not only for electromagnetic interference suppression but also for thermal shielding in electronic circuits. [ABSTRACT FROM AUTHOR]