Magnetic properties of hematite (α − Fe2O3) nanoparticles synthesized by sol-gel synthesis method: The influence of particle size and particle size distribution
| Autor: | Matjaz Panjan, Lazar Kopanja, Vesna Damnjanovic, Jelena Lazovic, Martin Kopáni, Biljana Vucetic Tadic, Marin Tadic |
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| Rok vydání: | 2019 |
| Předmět: |
particle size effects
iron oxide Morin transition Materials science Iron oxide sol-gel synthesis 02 engineering and technology Hematite 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry.chemical_compound hematite ([alpha] - Fe2O3) superparamagnetism (SPION) chemistry Chemical engineering α fe2o3 nanoparticles visual_art Particle-size distribution visual_art.visual_art_medium Particle size 0210 nano-technology Sol-gel |
| Zdroj: | Journal of Electrical Engineering |
| ISSN: | 1339-309X |
| DOI: | 10.2478/jee-2019-0044 |
| Popis: | Using the sol-gel method we synthesized hematite (α − Fe2O3) nanoparticles in a silica matrix with 60 wt % of hematite. X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra of the sample demonstrate the formation of the α − Fe2O3 phase and amorphous silica. A transmission electron microscopy (TEM) measurements show that the sample consists of two particle size distributions of the hematite nanoparticles with average sizes around 10 nm and 20 nm, respectively. Magnetic properties of hematite nanoparticles were measured using a superconducting quantum interference device (SQUID). Investigation of the magnetic properties of hematite nanoparticles showed a divergence between field-cooled (FC) and zero-field-cooled (ZFC) magnetization curves and two maxima. The ZFC magnetization curves displayed a maximum at around T B = 50 K (blocking temperature) and at T M = 83 K (the Morin transition). The hysteresis loop measured at 5 K was symmetric around the origin, with the values of coercivity, remanent and mass saturation magnetization H C10K ≈ 646 A/cm, (810 Oe), M r10K = 1.34 emu/g and M S10K = 6.1 emu/g respectively. The absence of both coercivity (HC300K = 0) and remanent magnetization (Mr300K = 0) in M(H) curve at 300 K reveals super-paramagnetic behavior, which is desirable for application in biomedicine. The bimodal particle size distributions were used to describe observed magnetic properties of hematite nanoparticles. The size distribution directly influences the magnetic properties of the sample. |
| Databáze: | OpenAIRE |
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