Kumio Nago

Microstructures and Magnetic Properties of Fe-(Ta,Nb,Zr)-N Alloy Films

The microstructures and magnetic properties of Fe-(Ta, Nb, Zr)-N alloy films near the eutectic composition were studied. These new soft magnetic alloy films were prepared by N2 reactive sputtering. The structures and magnetic properties were changed by annealing or by adjusting the ratio of the N2 partial pressure to the total gas pressure. Film structures were investigated by X-ray diffraction and TEM, and the following results were obtained, (i) As-prepared films consisted of an amorphous-like phase; (ii) annealed films were a homogeneous mixture of finegrained ¿-Fe and (Ta, Nb, Zr) nitrides; (iii) films annealed at higher temperatures consisted of larger grains of both ¿-Fe grains and (Ta, Nb, Zr) nitrides. Among these, the films (ii) exhibit good soft magnetic properties, small magnetostriction and a saturation magnetization as high as 1.6 T. The soft magnetic properties of Fe-Ta-Zr-N alloy films also had better thermal stability.