The present Diploma thesis provides an original synthesis for the preparation magnetic cobalt chromite nanoparticles (CoCr2O4 NPs) well dispersed in non-polar solvents and extensive structural, morphological, phonon and magnetic characterization. Particular emphasis is on determination of the spiral magnetic structure in CoCr2O4 NPs prepared by various procedures such as hydrothermal synthesis and sol-gel method. CoCr2O4 NPs with diameters in the range of 3.0 - 4.1 nm are prepared by high temperature hydrothermal method. For the first time, the CoCr2O4 NPs are stable in non-polar solvents and they are prepared by one-step synthesis without post treatment. The structure of prepared NPs is refined by Rietveld analysis. Size of prepared NPs is determined and compared using various techniques as powder X-ray diffraction (PXRD), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). Magnetic measurements reveal the transition from superparamagnetic (SPM) state to super spin glass - like (SSG) state. From a.c. susceptibility measurements, the spin dynamics studies and strength of inter-particles interaction are investigated. CoCr2O4 NPs with mean diameter of 26.9(1) nm are prepared by sol-gel method. The magnetization measurements reveal the transition from superparamagnetic to...
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:333509 |
| Date | January 2015 |
| Creators | Zákutná, Dominika |
| Contributors | Nižňanský, Daniel, Honecker, Dirk Olaf |
| Source Sets | Czech ETDs |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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