Ferromagnetic Resonance Study of Fe100-xCox/GaAs(001) (x ^|^lt; 11) Deposited by RF Magnetron Sputtering

Abstract

The Fe 100x Co x alloy thin films with dilute Co concentrations (x < 11) were prepared on GaAs(001) substrates by RF magnetron sputtering, and their dynamic magnetic properties were investigated by ferromagnetic resonance spectroscopy operating at Q-band (35 GHz). The magnetization curves measured by VSM show clear dependence on the in-plane field directions, indicating bcc Fe 100x Co x films were epitaxially grown on the substrates. The ferromagnetic resonance linewidths include both intrinsic and extrinsic magnetic damping. The origins of the latter were examined to extract the intrinsic damping. The estimated upper bounds of the Gilbert damping constants, caused by the intrinsic damping, depend on the Co compositions; the damping is accelerated as Co concentration increases in the region with x < 11.

Magnetostriction Behaviors of Fe_{100–<i>x</i>}Co_<i>x</i> Alloy Epitaxial Thin Films under Rotating Magnetic Field

“…Therefore in order to investigate the basic magnetostriction properties, it is useful to prepare epitaxial thin films, since the crystallographic orientation can be controlled by the substrate orientation. Fe-Co epitaxial films have been prepared on single-crystal substrates of GaAs [11][12][13][14][15][16] , MgO [17][18][19][20][21][22][23] , MgAl 2 O 4…”

Crystallographic anisotropy of the intrinsic Gilbert damping for single-crystalline Fe film

“…In ferromagnetic materials, the strength of the spin-orbit interaction is responsible for both the static and dynamic properties of magnetization, for example, a crystalline magnetic anisotropy and magnetization damping. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Thus, similar to the crystalline magnetic anisotropy, one can expect that the Gilbert damping constant governing the magnetization damping will also show a crystallographic anisotropy. However, it is still unclear whether the Gilbert damping constant has crystallographic anisotropy.…”

“…Generally, the ferromagnetic resonance (FMR) linewidth is measured to determine the Gilbert damping constant. [12][13][14][15][16][17][18][19] The linewidth is, however, not simply in proportion to the intrinsic Gilbert damping constant because extrinsic contributions such as two mangnon scattering (TMS) and inhomogeneous line-broadening (ILB) also increase the FMR linewidth. 11,16) To evaluate the intrinsic Gilbert damping constant precisely, those extrinsic contributions must be excluded.…”

“…The out-of-plane angular dependence of the linewidth is typically measured to extract the intrinsic Gilbert damping constant from the FMR spectrum data. [12][13][14][15][16][17][18][19] However, in the case of single-crystalline films, the out-ofplane angular dependence of the damping constant should be considered. Namely, we need an alternative method to evaluate the extrinsic contributions at a given crystallographic axis.…”

Large anisotropy of Gilbert damping constant in L21-ordered Co2FeSi film

“…3,17,18) For spintronics applications, it is important to understand the anisotropic behavior of ¡; however, few experimental reports on its anisotropy exist. 13,19,20) In addition, in order to discuss the anisotropy of the intrinsic Gilbert damping, it is important to separate extrinsic contributions such as two-magnon scattering (TMS) and inhomogeneous line-broadening (ILB), because they are also anisotropic.…”