Investigation of Structure, Microstructure and Magnetic Properties of Nano-Crystalline Zn Ferrite Synthesized at High Temperature | ||||
| Egyptian Journal of Solids | ||||
| Article 4, Volume 34, Issue 2, 2011, Page 41-49 PDF (844.67 K) | ||||
| DOI: 10.21608/ejs.2011.148870 | ||||
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| Abstract | ||||
| Zinc ferrite nano-material was prepared by direct fusion of ZnO with Fe in air. The morphological and structural properties of the system under study were investigated by scanning electron microscope (SEM) and X-ray powder diffraction (XRD) applying MAUD and Win-Fit programs. The X-ray studies show the coexistence of two phases. The major phase (66.66%) was determined to be the cubic spinel phase of ZnFe2O4 with average apparent crystallite size of about 48.7 nm and 81.5 nm respectively for Dβ and DF, while the minor phase of ZnO (33.33%) has hexagonal structure. The studied zinc ferrite present a uniform microstructure in the form of spherical grains as given by SEM. The type and density of defects as determined by electron spin resonance (ESR) are free spins with density 3.92x1023 cm-3. The presence of the ZnO phase may enhance the creation of Zn vacancies as surface defects that give rise to free spins. The magnetic properties of the system were studied using a vibrating sample magnetometer (VSM) at room temperature under a maximum field of 20 KOe. The coerricivity (HC), approximate saturation magnetization (Ms), remnant magnetization (Mr) and Curie temperature (TC) are determined. The low value of Ms is attributed to the high value of annealing temperature that allowed the formation of a better degree of crystallinity, i. e. smaller degree of inversion which enhances the magnetization. Also the absence of magnetic saturation at 20 KOe seems to be due to the effect of both the surface spin disorder in nano regime and the magnetic moment bearing ZnO impurity phase. The present magnetic investigations argue a ferrimagnetic character of the system under study. | ||||
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