Effect of Doping Elements on the Damping Constant of $({\hbox {Ni-Fe}})_{1-{ x}}{\hbox {M}}_{ x}$ (${\hbox {M}}={\hbox {Ga}}$, Ag, Mo, and W) Films

Abstract

This paper describes the relationship between the damping constant α and saturation magnetostriction λs of (Ni-Fe)1-xMx (M=Ga, Ag, Mo, and W; 0 <; x ≤ 0.10) films to clarify the effect of doping elements on α and other magnetic properties in these films. For M=Ga and Ag, the change of α with x is closely related with that of λs, while it is not consistent with that of λs when M = Mo and W. These results suggest that both α and λs are correlated with each other as the single fcc Ni-Fe phase remains unchanged with x for M=Ag and Ga, while that α and λs are independent from each other because of coexistence of fcc Ni-Fe and new phases when M=Mo and W. Therefore, it is pointed out that α can be controlled effectively by selecting the doping elements which do not induce a new phase in the Ni-Fe binary alloy, but one should be careful about a change in magnetoelastic properties which may deteriorate magnetic softness. These results for M=Ga and Ag also suggests that (Ni-Fe)1-xMx films are good examples to give evidence that the magnetoelastic energy Eσ has the same intrinsic origin with α.