MAGNETIC HYSTERESIS PROPERTIES OF BAFE12-XINXO19 CERAMIC FERRITES WITH C-AXIS ORIENTED GRAINS

To 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)(x)O19 series in single-crystal form have shown that magnetization 4-pi-M and anisotropy field H(k) decrease sharply with increasing x. Since hysteresis loops with optimum energy products require uniformly small grains (1 to 3-mu-m), sintering temperatures were carefully controlled over a range from 1180 to 1075-degrees-C for 2 h, depending on In content. For nominal values of x ranging from 0 to 1.5, square hysteresis loops with H(c) values decreasing from 3500 to 150 Oe were recorded with a high-field hysteresisgraph. The effective H(k) values were measured and compared with single-crystal data to estimate the degree of grain alignment for each composition.