Effect of Nitrogen Addition on the Soft Magnetic Properties of High-BS Fe-N-Al-O Films

We investigated the effect of N addition on the magnetic properties and microstructure of Fe-N-Al-O alloy films. The N concentration in films was varied from 0 to 5 at%. The addition of a small amount (∼5 at%) of N into the Fe-Al-O alloy system is effective for increasing the resistivity without causing a remarkable decrease of Bs, and for improving the soft magnetic properties. The optimal film for soft magnetism has a magnetostriction of less than 1.8 × 10-6 and a magnetic thermal stability of up to 300°C. No change in grain size is clearly observed when the N element is added in the Fe-Al-O alloy system. However, with an increase in the N alloy concentration, the N solubility in α phase increases and the crystal orientation of α (110) becomes strong.