부산대학교 도서관

MnxZn1-xFe2O4 (x = 0.5, 0.6, 0.7) ferrite nanoparticles were synthesized by a thermal decomposition method. The synthesized particles were identified as pure spinel ferrite structures by x-ray diffraction analysis and they were calculated to be 15-20 nm in diameter by the Scherrer equation, depending on the composition. Ferrite nanoparticles are spherical in shape with a slightagglomeration in the FE-SEM image, and the particle size is about 20 nm, which was consistent with the value obtained bythe Scherrer equation. The lattice parameters of ferrite nanoparticles monotonously decreased from 8.358 Å to 8.389 Å as themanganese concentration increased from 0.5 to 0.7. As the manganese content increases from x = 0.5 to 0.7, the saturationmagnetization value increases from 76 emu/g to 63 emu/g. MnxZn1-xFe2O4 toroidal samples were prepared by sintering ferritenanoparticles at 1,250 oC and exhibited faceted grain morphology in FE-SEM images with a grain size of about 3 umregardless of manganese content. The cutoff frequency of the ferrite toroidal sample was estimated to be about 3MHz fromthe broad maximum point in the plot of imaginary magnetic permeability (μ”) vs. frequencies, which seems to be associatedwith domain wall resonance.