Magnetic properties and microstructure of BaFe11.6-2xTixMxO19 (M = Co, Zn, Sn) compounds

BaFe11.6-2xMxTixO19 (M = Co2+, Zn2+, Sn2+) compounds in powder form were prepared by a sol-gel route. The materials were annealed at several temperatures and characterised. The results showed that the cationic substitutions (x) lowered the coercivity (H-ci), presumably due to the decrease of the magnetocrystalline anisotropy of the doped Ba ferrites. Sn-Ti mixtures decreased H-ci faster than Zn-Ti and Ti-Co; however, lower magnetisations were achieved. In this regard, BaMZn-Ti showed slightly higher magnetisation than BaMTi-Co compounds. The effect of the heat-treatment temperature was to increase the magnetisation, following a slight coercivity decrease due to grain coarsening. (C) 2003 Elsevier B.V. All rights reserved.