Influence of magnetostriction on damping constant of NixFe1−x film with various Ni concentrations (x)

Abstract

We investigated the influence of magnetostriction on the damping constant (α) of 50-nm-thick NixFe1−x polycrystalline films, with x ranging from 0.66 to 0.86. In the experiments, α and the saturation magnetostriction (λs) were evaluated with high accuracy, which allowed for an interesting finding suggesting a simple relation between α and λs. In the range of positive λs, α slightly increases as x decreases, whereas α increases from 0.009 to 0.012 with increasing x for negative λs values. α reaches a minimum when λs is around zero at x = 0.78. These results demonstrate that different behaviors of α depend on positive or negative values of λs. Therefore, particular attention should be paid to the change in magnetoelastic properties and the deterioration of magnetic softness when adjusting α of magnetically soft films.