The effects of annealing temperature on the magnetic properties of Fe _75.5Zr _8.3N _16.2/SiO ₂ multilayer thin films

[Fe _75.5Zr _8.3N _16.2(800 Å)/SiO ₂(250 Å)] ₁₀ multilayer thin films were fabricated by using an rf magnetron reactive sputtering method. The saturation magnetic flux density and the coercive force were measured as functions of the annealing temperature. The effective permeability at high frequencies and the thermal stability were also examined. The magnetic properties of the [Fe _75.5Zr _8.3N _16.2(800 Å)/SiO ₂(250 Å)] ₁₀ multilayer thin films showed a saturation flux density of 1.08 T, a coercive force of 0.41 Oe, and an effective permeability of about 4000 at 1 MHz. The observed good magnetic softness is attributed to the prohibition of the growth of α-Fe grains due to the precipitation of nanocrystalline ZrN particles. The sizes of the α-Fe grains and the nanocrystalline ZrN particles were 40-50 Å and 10-15 Å, respectively. The effective permeability of a FeZrN single-layer film decreased rapidly when the frequency exceeded 5 MHz. On the contrary, the effective permeability of a multilayer film was around 2200 up to a frequency of 40 MHz.