Improvement in magnetic properties of Sm-Fe-N flakes by annealing under Zn vapor

A new method for improving the coercivity and stability of magnetic properties of Sm-Fe-N flakes by annealing under Zn vapor is proposed. Annealing of the flakes at 380/spl deg/C with Zn foil under an Ar atmosphere deposited a Zn film, resulted in formation of Fe-Zn compounds on the surface of the flakes, and improved the coercivity by 2-5 kOe. The deposition of approximately 1 wt.% Zn was enough to obtain a remarkable improvement in the coercivity. The Zn-treatment also suppressed the deterioration of the coercivity and the remanence due to exposure to air at 300/spl deg/C, and an increase in the amount of Zn caused an increase in their stability. Therefore, the proposed method is expected to be a promising method for improving magnetic properties and their stability of Sm-Fe-N flakes by Zn-treatment.