Magnetic and structural properties of M-type barium hexaferrite prepared by co-precipitation

被引:112
|
作者
Shepherd, Philip [1 ]
Mallick, Kajal K. [1 ]
Green, Roger J. [1 ]
机构
[1] Univ Warwick, Sch Engn, Coventry CV4 7AL, W Midlands, England
关键词
barium hexaferrite; complex permeability; magnetic properties;
D O I
10.1016/j.jmmm.2006.08.046
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Stoichiometric and single-phase barium hexaferrite (BaM) has been synthesized by co-precipitation and an additional solid state preparative method using high-purity nitrates, oxides and carbonates of iron (111), barium (11) and ammonium hydroxide. The isochronally and isothermally measured permeability and magnetic loss tangents over 1 MHz-1 GHz in frequency remained moderately constant until a sintering temperature of 1300 degrees C where relative permeability of 1.3 and loss tangent of 0.06 at 1 GHz, indicate high-frequency magnetic characteristics for BaM. TGA/DTA studies showed the hexaferrite formation temperature was found to be 1050 degrees C. The apparent densities before and after each firing cycle showed a monotonic increase. X-ray diffraction studies established the presence of a single phase with the theoretical space group P63/mmc, and computed cell parameters of a = b = 5.895 angstrom and e = 23.199 angstrom. The samples exhibited a Curie point (T-c) of 452 degrees C and displayed ferromagnetic resonance characteristics centred on a frequency of 500 MHz. (C) 2006 Elsevier B.V. All rights reserved.
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页码:683 / 692
页数:10
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