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 N
₂
reactive sputtering. The structures and magnetic properties were changed by annealing or by adjusting the ratio of the N
₂
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 α-Fe and (Ta, Nb, Zr) nitrides; (iii) films annealed at higher temperatures consisted of larger grains of both α-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.