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R. Sato Turtelli, V. Giap, W. Nunes, R. Grössinger, M. Knobel:
"Magnetic properties of nanocrystalline CoFe2O4 synthesized by modified citrate-gel method";
Journal of Magnetism and Magnetic Materials, 320 (2008), 14; S. e339 - e342.

Nanocrystalline CoFe2O4 with an average grain size of about 40 nm was successfully prepared by a modified citrate-gel method. At temperatures of 3 and 300 K, the measured coercive fields are 0.43 and 0.07 T and the magnetizations at 7 T are 89 and 83 emu/g, respectively. At room temperature, the longitudinal and transversal magnetostriction values are −130 and 70 ppm, respectively. The contribution of a disordered magnetic phase was detected by the occurrence of a peak in the ac-susceptibilities curves at around 250 K. The temperature dependence of the field-cooled and zero field-cooled low-field magnetization showed a larger irreversibility below this temperature. This disordered phase behaves like a spin-glass, which is coexisting with the ferrimagnetically ordered main phase

Cobalt ferrite; Citrate-gel method; Hysteresis loop; Magnetization

http://dx.doi.org/10.1016/j.jmmm.2008.02.067

http://dx.doi.org/10.1016/j.jmmm.2008.02.067