Properties of Cr-substituted M-type barium ferrites prepared by nitrate-citrate gel-autocombustion process
The Cr-substituted M-type barium hexaferrites, BaFe12-xCrxO19, with x = 0.0 - 0.8 have been successfully prepared by nitrate-citrate auto-combustion process using citric acid as a fuel/reductant and nitrates as oxidants. The resulting precursors were calcined at 1100 °C for 1 h and followed by sinte...
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| Main Authors: | , |
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| Format: | Journal |
| Published: |
2018
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| Subjects: | |
| Online Access: | https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=33747749557&origin=inward http://cmuir.cmu.ac.th/jspui/handle/6653943832/61942 |
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| Institution: | Chiang Mai University |
| Summary: | The Cr-substituted M-type barium hexaferrites, BaFe12-xCrxO19, with x = 0.0 - 0.8 have been successfully prepared by nitrate-citrate auto-combustion process using citric acid as a fuel/reductant and nitrates as oxidants. The resulting precursors were calcined at 1100 °C for 1 h and followed by sintering at 1200 °C for 12 h in oxygen atmosphere. The ferrites were systematically investigated by using powder X-ray diffractometer (XRD), magnetic hysteresis recorder, Mössbauer spectrometer, and scanning electron microscope (SEM). The XRD data show the formation of pure magnetoplumbite phase without any other impurity phases. Both a and c lattice parameters calculated by the Rietveld method systematically decrease with increasing Cr content. The effects of Cr3+ions on the barium ferrites were reported and discussed in detail. The site preference of Cr3+and magnetic properties of the ferrites have been studied using Mössbauer spectra and hystereses. The results show that the magnetic properties are closely related to the distributions of Cr3+ions on the five crystallographic sites. The saturation magnetization systematically decreases, however, the coercivity increases with Cr concentration. The magnetization and Mössbauer results indicate that the Cr3+ions preferentially occupy the 2a, 12k, and 4fVIsites. The average size of hexagonal platelets obtained by SEM photographs tends to decrease with respect to Cr content. © 2005 Elsevier B.V. All rights reserved. |
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