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Magnetic Ceramics
Published in Lionel M. Levinson, Electronic Ceramics, 2020
The magnetoplumbite structure is hexagonal and therefore has one major axis, the c axis, which is important magnetically. The magnetoplumbite formula is MFe12O19, or M•O6Fe2O3, where M can be Ba, Sr, or Pb. The Fe2O3 can be partially replaced with Al, Ga, Cr, or Mn. Variations of the magnetoplumbite structure involve combinations of the Ba, Sr, or Pb oxides with spinel, forming oxides to produce new complex layered structures.
Tailoring the magnetic properties of M-type strontium ferrite with synergistic effect of co-substitution and calcinations temperature
Published in Journal of Asian Ceramic Societies, 2021
Sachin Kumar Godara, Varinder Kaur, S.B. Narang, Gurpreet Singh, Mandeep Singh, Gopala Ram Bhadu, Jayesh C. Chaudhari, P.D. Babu, Ashwani Kumar Sood
Figure 1a reveals that the X-ray diffractograms of SrZnxZrxFe12-2xO19(x = 0.00) samples at different calcinations temperature. The figure clearly shows that magnetoplumbite phase starts appearing at temperature ≥800°C. However, secondary phase (α-Fe2O3) was noticed up to 950°C calcinations temperature beyond that the samples would be phase pure and highly crystalline in nature. This shows that the minimum temperature of phase pure SrM formation is ≈1000°C. Figure 1b shows the X-ray diffractograms of SrZnxZrxFe12-2xO19 (x = 0.00–1.00) samples which were calcined at 1000°C. A comparison of the reported (ICSD 98–002-6353, structural data of SrFe12O19) and experimental peak positions shows that a) the absence of secondary phases such as α-Fe2O3 and SrFe2O4 and b) Zn2+-Zr4+ cations have successfully replaced the Fe3+ ions in the SrM unit cell. Further, Figure 1c clearly reveals the shifting of two highest intensity peaks (107 and 114) toward lower 2θ with increase in “x”. This shifting of peak position is indicative of lattice expansion which is due to higher atomic radii of Zn2+ (0.74 Å) and Zr4+ (0.80 Å) in comparison to Fe3+ (0.64 Å) [43].
A cost-effective method for obtaining single magnetic cotton yarns
Published in The Journal of The Textile Institute, 2022
Iuliana G. Lupu, Marian C. Grosu, Oana Cramariuc, Florin Tudorache, Daniela C. Nastac, Horatiu I. Hogas
Based on insight from previous research (Grosu et al., 2016; 2018) where we studied magnetic twisted cotton yarns, several mixtures containing barium hexaferrite (BaFe12O19) as hard magnetic powder were chosen to cover the cotton single yarn. We used barium hexaferrite with a mass percentage between 10% and 50%, two polymers in liquid state (polyvinyl acetate and polyurethane) and glycerol. The barium hexaferrite was supplied by Rofep, Romania. It is a hexagonal hard magnet with magnetoplumbite structure widely used as ceramic permanent magnet. Its basic characteristics were presented in our previous study (Grosu et al., 2018).