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Remanence of the interparticle interactions and its influence on the microwave absorption in Co-ferrite |
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| Authors: | ME Mata-Zamora H Montiel G Alvarez JF Barrn H Arriola JM Saniger R Valenzuela |
| Institution: | aCentro de Ciencias Aplicadas y Desarrollo Tecnologico de la, Universidad Nacional Autonoma de México, Apartado Postal 70-360, Coyoacan DF 04510, Mexico bDepartamento de Quimica Inorganica y Nuclear, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Coyoacan DF 04510, Mexico cDepartamento de Materiales Metálicos y Cerámicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Coyoacan DF 04510, Mexico |
| Abstract: | Cobalt ferrite nanoparticles were obtained by the sol–gel method at several annealing temperatures: 400, 450, 500, 550 and 600 °C. X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed the formation of the spinel phase with a nanoparticle size in the 17–26 nm range as function of the annealing temperature. The Mössbauer spectra at room temperature showed the presence of a partial inverse spinel structure. Saturation magnetization and the coercive field are strongly dependent on the annealing temperature and they can be associated with variations of the nanoparticles size. Microwave power absorption (MPA) (dP/dH) measurements were carried out as a function of DC field (HDC) in asymmetric sweeps in the 0 kOe HDC9 kOe range, at X-band (9.4 GHz), for all annealing temperatures. The large hysteresis in the MPA is due to interparticle interaction associated with its demagnetizing-like nature. |
| Keywords: | Henkel plot Microwave absorption Cobalt ferrite |
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