Abstract
BaFe12-2xCoxTix-ySnyO19 powders with x = 0 - 0.9 and y = 0 - 0.4 have been prepared by the glass crystallization method. The individual single crystalline and single domain particles possess a perfect M-type structure and a narrow log-normal grain distribution. The mean particle diameters for x ≈ 0.8 and y = 0 - 0.4 are between 40 and 80 nm and the mean aspect ratios between 3 and 6; the diameters can be varied in between 10 nm and 1μm. Magnetization data are diminished by an effective nonmagnetic layer (about 1nm thick) parallel to the basal surface of the hexagonal platelets. The coercivity is decreased by substitutions of Co-Ti, Co-Si, Co-Ge, Co-Sn, and Co-Zr. Coercivity and its temperature dependence is studied in detail for the system BaFe10.4(Co,Zn)0.8(Ti,Sn)0.8O19. The magnetic interaction effects between the individual particles are comprehensively discussed.
