Magnetization of Ultrafine Cadmium Ferrite Particles |
Eun-Jung Park |
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ABSTRACT |
Ultrafine cadmium ferrite particles have been investigated by X-ray diffractometry, transmission electron microscopy and SQUID magnetometry. All peaks of X-ray diffraction patterns are broad, but correspond to a cubic spinel structure with the lattice constant of 8.65 $AA$. The average particle size determined by TEM is 9.7 nm and the size distribution of particles is not normal, but lognormal. The maximal magnetization measured at 5 K was 17.7 emu/g. The experimental data show a transi-tion from a disorder ferrimagnetic phase to a spin-glass phase (i.e. reentrant behavior) with a freezing temperature (T$_$f/) of 30 K. Superparamagnetic behavior of the particles is confirmed by the coincidence of the plots of M vs. H/T for 100 and 300 K. |
Key words:
Ultrafine particles, Particle size distribution, Magnetization, Superparamagnetism |
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