The effects of La–Zn substitution on the magnetic properties of Sr-magnetoplumbite ferrite nano-particles

The La–Zn substituted Sr-Magnetoplumbite ferrite LaxSr1−xZnxFe12−xO19 (x=0–0.6) fine particles were prepared to investigate the effects of the substitution on the magnetic properties of the samples. It is observed, with increasing substitution rate, that the saturation magnetization Ms as well as the magnetocrystalline anisotropy constant KU1 increased up to a maximum for about x=0.3, then decreased rapidly. The value of dHc/dT also reduced rapidly from about 5.5 Oe K−1 (for x=0) to −0.5 Oe K−1 (for x=0.4). A qualitative explanation was given with respect to the hypothesis of crystalline electronic field and the single ion model.