The effect of La–Zn substitution on the microstructure and magnetic properties of barium ferrites

The effect of La–Zn substitution on the microstructure and magnetic properties of Ba 1− x La x Fe 11.6− x Zn x O 19 (0 ≤ x ≤ 0.8) ferrites synthesized by sol–gel method was investigated. When 0 ≤ x ≤ 0.6, there mainly exists hexagonal ferrite phase in the samples, the lattice constants a and c decrease monotonously with the increase of x. The magnetization σ increases with the change of x to the maximum at x = 0.6 and then decreases, whereas the coercivity Hc, the anisotropy field H A and Curie temperature Tc decrease monotonously. In order to obtain the maximum magnetization, the sample with more substitution amount should be annealed at more high temperature. The results of the experiment are explained qualitatively in the paper.