Preparation of barium ferrite films with high Fe/Ba ratio by sol–gel method

摘要

Hexagonal BaFe₁₂O₁₉ ferrite (BaM) thin films were prepared on Si (100) substrate successfully by sol–gel technology and post annealing. The results showed the BaM phase can be formed and crystallized into c-axis textured grains even when the Fe/Ba ratio of the precursor varied from 6.5 to 9.5. However, the behavior of the saturation magnetization (M _s) and intrinsic coercivity (H _c) depended strongly on the Fe/Ba ratio and annealing temperature (T _a) varied from 700 to 900 °C. The M _s and H _c values deceased with an increase of Fe/Ba ratio, for instance, were about 290 emu/cm3 and 4,200 Oe for the Fe/Ba = 6.5 film but only 116 emu/cm3 and 2,300 Oe for the Fe/Ba = 9.5 film. The M _s and H _c values of the Fe/Ba ratio = 6.5 film increased monotonously with increasing T _a, were about 120 emu/cm3 and 2,500 Oe at T _a = 800 °C, and reached to 345 emu/cm3 and 4,600 Oe at T _a = 950 °C.