Abstract
A synthesis and magnetic properties of Ca-La-Co M-type (Ca1-xLaxCoyFen-yOa) ferrite magnets were investigated. A M-type singlephase calcined powder was synthesized with a composition of x=0.5, y=0.2-0.3 and n=10.0-10.8. And a very high magnetic properties of Jr=0.453 T (4530 G) and HcJ=435 kA/m (5470 Oe) were obtained with a composition of x=0.5, y=0.3 and n=10.4 in sintered magnets. The magnetic properties greatly exceeds that of Sr-La-Co M-type ferrite, which has been the highest grade M-type hard ferrite. The improvement can be attributed to the 20% increase in anisotropic magnetic field in comparison to that of Sr-La-Co M-type ferrite. The temperature dependence of coercivity was also improved to ΔHcJ/HcJ/ΔT=0.11 %/K, compared to 0.16 %/K in Sr-La-Co ferrites.
