Magnetization and Magnetic Entropy Change in Superparamagnetic Co-Ferrite Nanoparticle

In order to the magnetization and magnetic entropy change for superparamagnetic ferrite nanoparticles, ultrafine cobalt ferrite particles were synthesized using a mircoemulsion method. The peak of X-ray diffraction pattern corresponds to a cubic spinel structure with the lattice constant 8.40 . The average particle size, determined from X-ray diffraction line-broadening using Scherrer`s, is 7.9 nm. The maximal magnetizations measured at 5 and 300 K are 24.3 emu/g and 17.2 emu/g, respectively. Superparamagnetic behavior of the sample is confirmed by the coincidence of the M vs. H/T plots at various temperatures. According to the thermodynamic theory, magnetic entropy change decreases with increasing temperature.