Q-Band Ferromagnetic Resonance Study of Fe Thin Films on GaAs(001) Deposited by RF Magnetron Sputtering

The magnetic properties of epitaxial Fe(001) films, prepared on GaAs(001) substrates by RF magnetron sputtering, were investigated by ferromagnetic resonance spectroscopy operating at Q-band (35 GHz). The in-plane angle dependence of the resonance fields showed four-fold magnetic anisotropy with an easy (hard) direction along [100] ([110]). The anisotropy constant was slightly smaller than the magnetocrystalline anisotropy constant of bulk Fe. Ferromagnetic resonance linewidths, caused by the magnetic damping of Fe films, were narrow (<;70 Oe) and independent of the in-plane magnetic field directions. It will be shown that the observed linewidth gives good estimate of the upper bound of the Gilbert-type damping in Fe thin films.