STRUCTURE AND MAGNETIC PROPERTIES OF MAGNETIC NANOPARTICLES (Fe-R) (R = Fe, Tb, Dy, Co) FROM HIGH ENERGY MILLING PROCESS
Daftar Isi:
- One of the simple and effective preparation routes of nanosized magnetic particles is high-energymilling (HEM) process. In this method, the final properties of the particles obtained can be controlled by varying precursor composition, milling time and environment. This paper presentes the results of HEM process on microsize Fe powder of at least 95% weight fraction mixed with each microsize Co, Tb4O7 and Dy2O3 powders. The milling process was carried out in ethanol/water media for 40 hours. The phase analysis on the X-ray diffraction pattern using Rietveld analysis method showed the formation of mixture phase of Fe, Fe3O4/γFe2O3 with crystalline size of ~ 10 nm. This crystalline size of nanoparticles was confirmed by Transmission Electron Microscope (TEM) observation ensuring the formation of a single domain particle as a result of this milling process. Co atoms tend to partially replace Fe atoms on one of the Fe-site in the phase unit cell, while Tb and Dy atoms will just interstitially deform amorphous Fe oxide. These two mechanisms homogeneously occur within the samples and give no significant change to the structure of the initial phase. These two changes just impact on the formation of nanoparticles magnetic properties with the lowest magnetisation value reaching ~ 105 emu/g on powders with Co addition.Keywords: High Energy Milling, Magnetic nanoparticle, Fe, Tb4O7, Dy2O3, Co.