Please use this identifier to cite or link to this item: http://nopr.niscair.res.in/handle/123456789/9571
Title: Magnetic, dielectric and microwave absorption studies of Ba-CoTi hexaferrite — Epoxy composites
Authors: Singh, Praveen
Babbar, V K
Razdan, Archana
Goel, T C
Srivastava, S L
Keywords: Microwave absorption
Complex permeability
Complex permittivity
Microwave ferrite composites
Issue Date: Mar-2004
Publisher: CSIR
Series/Report no.: G 01N 25/00, 21/00
Abstract: The microwave absorption, complex permittivity and complex permeability studies of hexaferrite composites prepared with Ba(CoTi)<sub>x</sub>Fe<sub>12-2x</sub>O<sub>19</sub> wherein <i>x</i> varies from 0.0 to 1.0 in steps of 0.2 were made in frequency range from 8.0 to 12.4 GHz. The effect of Co<sup>2+</sup>Ti<sup>4+</sup> substitution and of microstructural variation on complex permeability, permittivity and microwave absorption have been analysed. The hexaferrite-composites with <i>x</i> > 0.0 exhibit significant dispersion in the complex permittivity (<img src='/image/spc_char/italics_e.gif' border=0><sub>r</sub>'- j<img src='/image/spc_char/italics_e.gif' border=0><sub>r</sub>'') with maximum value of <img src='/image/spc_char/italics_e.gif' border=0><sub>r</sub>'' is observed for <i>x</i> equal to 1.0. The dispersion in complex permeability (<img src='/image/spc_char/micro.gif' border=0><sub>r</sub>'-j<img src='/image/spc_char/micro.gif' border=0><sub>r</sub>'') is not significant and is attributed to the shielding effect of polymer matrix over the ferrite crystallites and to the low alternating electromagnetic field applied to the sample. The variation of reflection loss has been studied as a function of frequency (<i>f</i>), Co<sup>2+</sup>Ti<sup>4+</sup>content and thickness of the absorber. A maximum absorption of 16 dB (86%) is obtained for composites with <i>x</i> equal to 0.4 and of 2.8 mm thickness.
Description: 221-228
URI: http://hdl.handle.net/123456789/9571
ISSN: 0975-1041 (Online); 0019-5596 (Print)
Appears in Collections:IJPAP Vol.42(03) [March 2004]

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