Popis: |
The magnetic properties of substituted hard-magnetic M-type ferrites are surveyed. A combined La–Co substitution leads to magnets of compositions Ba1−xLaxFe12−xCoxO19 and Sr1−xLaxFe12−xCoxO19 (x= 0, 0.1, 0.2, 0.3, 0.4). Due to this substitution, the anisotropy as well as the coercivity increases. The effect of the ion size was studied on the system (Sr1−yCay)1−xLaxFe12−x Co0.75xFe2+0.25xO19 (x= 0.2, 0.4; y= 0, 0.33, 0.66, 1). Additionally, Sm substitution which leads to a strong increase of the coercivity was studied, but the effect on the anisotropy is small (1%). |