| 초록 |
Vibration energy harvesters have been widely studied due to their high power density given by strong kinetic energy sources. Among the vibration energy sources, multiferroic materials have been interested in practical applications due to its unique characteristic simultaneously exhibiting ferroelectric and ferromagnetic properties. Particularly, magnetoelectric (ME) composites reveal promising magnetical-mechanical-electrical coupling effects, which can be used for high-sensitive magnetic field sensors, transducers, memory and biomedical devices. In this study, Ni/Ferrites (CoFe2O4 or ZnFe2O4) core/shell nanoparticles were synthesized by hydrothermal method to induce self-bias magentoelectric (SME) effect, which can provide feasible responses for high magnetic or electric sensitivities without applying DC magnetic field. The bimagnetic interactions of core/shell nanoparticles directly affect the SME responses, so optimum magnetostriction was investigated by adjusting materials composition and core-shell thickness ratio. In order to characterize material and magnetic properties of core-shell nanoparticles, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED) and vibrating sample magnetometer (VSM) measurements were performed. |
