Ferromagnetic resonance investigation of magnetic anisotropy of ion-synthesized iron-silicide thin films

40 keV iron ions have been implanted into single-crystal silicon wafers at room temperature. As a result, thin iron-silicide films were synthesized in the near-surface region of substrates. Scanning magnetooptical Kerr effect studies showed that some films had the uniaxial magnetic anisotropy. The coercive force determined in the direction of the easy magnetization for films with the magnetic anisotropy increased with the increase in the implantation fluence. However, ferromagnetic samples became isotropic when the dose of the order of 2.6×1017 cm–2 was reached. Ferromagnetic resonance studies showed that the resonance linewidth in isotropic samples increased with the temperature decrease. It was found that the ferromagnetic resonance linewidth for samples with the uniaxial anisotropy was less than that for isotropic ones. The observed behavior of resonance spectra can be explained on the basis of the model taking into account the effect of thermal fluctuations of the resonance line shape in disperse ferromagnets.