Effect of Si Composition on Static and Dynamic Magnetic Properties of Fe–Si Films

This article describes the effect of Si composition (
$x$
) on static and dynamic magnetic properties of 30 nm-thick FexSi100-x polycrystalline films (
$9.7\le x \le21.7$
). In the experiments, in-plane and out-of-plane effective damping constant (
$\alpha _{\mathrm {//}}$
,
$\alpha _{\bot }$
) were investigated by broadband ferromagnetic resonance (B-FMR). The difference between
$\alpha _{\mathrm {//}}$
and
$\alpha _{\bot }$
in Fe–Si films indicated that the damping constant was attributed to extrinsic damping for
$\alpha _{\mathrm {//}}$
. Moreover, a simple relation between the saturation magnetostriction (
$\lambda _{\mathrm {s}}$
) and the in-plane effective damping can be obtained for Fe–Si films. In the range of
$\lambda _{\mathrm {s}}$
less than (2.59 ± 0.05)
$\times 10^{-5}$
,
$\alpha _{\mathrm {//}}$
slightly increased as
$x$
was decreased. Meanwhile, for
$\lambda _{\mathrm {s}}$
more than (2.59 ± 0.05)
$\times 10^{-5}_{,}\,\,\alpha _{\mathrm {//}}$
significantly increased as
$x$
was increased except
$x$
=
$15.7. \alpha _{\mathrm {//}}$
reached a minimum as
$\lambda _{\mathrm {s}}$
was (2.59 ± 0.05)
$\times 10^{-5}$
for
$x$
= 13.7. These results demonstrate that the different behavior exhibited by
$\alpha _{\mathrm {//}}$
depends on
$\lambda _{\mathrm {s}}$
.