Magnetocrystalline Anisotropy of M-Type Sr-Ferrite Containing Lanthanum and Cobalt.

Magnetic Properties of La-Co Substituted Ba Ferrite Thin Films Prepared by a Sol-Gel Method

“…Therefore, the magnetization doesn't depend on the thickness of La-CoBaM layer. However, Nishio et al [4] reported that the magnetization of (La-Co) 0.3 -SrM bulk was about 380 emu/cm 3 , which was higher than these La-CoBaM films. This is because the density of these thin films might decrease.…”

“…The BaM films that prepared by sol-gel method have been studied because of expectation that annealing temperature can be reduced [1][2][3]. Besides, it has been reported on La-Co ions substitution for SrM that the saturation magnetization as well as the magneto crystalline anisotropy constant of magnetoplumbite ferrite fine particles was increased [4]. However, when the BaM films directly coated on quartz substrates, Ba 2+ ions diffused into quartz substrates during post-anneal, then it was caused degradation of magnetic properties and crystallization of Si-O substrate.…”

Investigation on the La Replacement and Little Additive Modification of High-Performance Permanent Magnetic Strontium-Ferrite

“…The general formula of M-type ferrite is AFe 12 O 19 , where A = Ba or Sr, and a part of these elements can be replaced by rare-earth elements. Among them, a part of Fe could be substituted by cobalt (Co) to obtain better magnetic performance that would result in high intrinsic magnetization M s and anisotropic magnetic field strength H A [13][14][15][16][17][18][19]. Besides, the element at the A position can be substituted by other rare-earth elements, such as La, since La 3+ (1.17 Å), Ba 2+ (1.22 Å), and Sr 2+ (1.32 Å) share almost the same radius.…”

“…If only La is contained in the permanent magnet ferrite, the effect of improving B r and i H c will not be obvious. This is because when La and Co undergo a substitution reaction in the permanent ferrite, the ratio of La to Co needs to reach a certain value, which is not suitable for values which are too large or too small [3,[11][12][13][14][15][16][17][18]. Past studies usually designed a calcining La-Co system material formula to simultaneously achieve high B r and high i H c [3,[11][12][13][14][15][16][17][18].…”

“…In recent studies, a significant improvement has been made in SrFe 12 O 19 ferrite by a combined replacement of La 3+ in Sr 2+ site and Co 2+ in Fe 3+ , and the simultaneous substitution of lanthanum and cobalt could obviously enhance the intrinsic coercivity i H c when keeping the remanence B r invariant. However, past research has often designed a calcined La-Co base formula composition to acquire large B r and large i H c at the same time [13][14][15][16][17][18][19]. It ought to be noticed that the design of the formula requires the participation of valuable metal component cobalt to be used in the calcination formula in the form of oxide, such as Co 3 O 4 , which has a big hazard of mass production and greater cost.…”