Hgh-Performance Ferrite Magnets: M-Type Sr-Ferrite Containing Lanthanum and Cobalt.

Synthesis and magnetic properties of La-substituted M-type Sr hexaferrites

“…A variety of cation substitutions in M-type hexaferrites has been tested [2] in order to improve the saturation magnetization or coercivity. Some success was achieved with La-Co co-substituted ferrites; the increased energy product is mainly due to a constant saturation magnetization and an increase of coercivity in the substituted samples, which was shown to originate from an increased magneto-crystalline anisotropy [3,4]. Therefore, interest in the magnetic properties of La-Co cosubstituted as well as La-substituted hexagonal ferrites has revitalized.…”

Structure and Magnetic Properties of La3+-Substituted Strontium Hexaferrite Particles Prepared by Sol-Gel Method

“…Replacement of divalent Ba or Sr by trivalent La is associated with a valence change of one Fe 3+ to Fe 2+ per formula unit. Due to these reasons discussed above, many researchers have centered efforts on Ba 1--x La x Fe 12--x Zn x O 19 [8], LaFe 12 O 19 [9], and Ba 1--x (LRE) x Fe 12--x Co x O 19 [10]. However, the samples reported in these papers are prepared by using the ceramic process.…”

Magnetic anisotropy and magnetostriction of

“…The compound is only formed between 1380 and 1420 C [3]. Substituting simultaneously La and Co in Sr-or Ba-ferrite causes a remarkable improvement of the coercivity and its temperature dependence together with an increase of the anisotropy field [4]. The charge compensation leads to a Co 2þ state with an unquenched orbital momentum, which causes a higher anisotropy [5].…”