Magnetic hysteresis properties of BaFe12− x In x O19 ceramic ferrites with c -axis oriented grains
1991; American Institute of Physics; Volume: 70; Issue: 10 Linguagem: Inglês
10.1063/1.350022
ISSN1520-8850
AutoresGerald F. Dionne, James Fitzgerald,
Tópico(s)Magneto-Optical Properties and Applications
ResumoTo study the effects of reduced magnetic anisotropy on hysteresis loops of hard magnets for possible use in self-biased microwave devices, a new family of magnetically oriented (c-axis) In-substituted Ba ferrite was prepared by conventional ceramic techniques. Earlier studies of BaFe12−x(In,Sc)xO19 series in single-crystal form have shown that magnetization 4πM and anisotropy field Hk decrease sharply with increasing x. Since hysteresis loops with optimum energy products require uniformly small grains (1 to 3 μm), sintering temperatures were carefully controlled over a range from 1180 to 1075 °C for 2 h, depending on In content. For nominal values of x ranging from 0 to 1.5, square hysteresis loops with Hc values decreasing from 3500 to 150 Oe were recorded with a high-field hysteresisgraph. The effective Hk values were measured and compared with single-crystal data to estimate the degree of grain alignment for each composition.
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