Magnetic properties of epitaxial Fe3Si/MgO(001).
The composition dependence of the magnetic as well as structural properties of epitaxial 4–40 nm Fe3Si thin films on MgO(001) have been investigated using ferromagnetic resonance, superconducting quantum interference device magnetometry, and magneto-optical Kerr effect. Magnetic anisotropy energy, g factor, and magnetization were determined for different samples with Si concentrations of 20%, 25%, or 30% at room temperature. Additionally, different annealing procedures were applied. The magnetization was determined to be on the order of µ0M[approximate]1 T. It was found that the films have a dominating cubic anisotropy K4[approximate]3×103 J/m3 which depends on the thermal treatment of the film and is about 1 order of magnitude smaller than the one of bulk Fe. A small uniaxial in-plane anisotropy of interfacial nature was detected. The perpendicular uniaxial anisotropy term, which is dominated by an interface contribution, favors a perpendicular easy axis. From frequency-dependent ferromagnetic resonance measurements an isotropic g factor was extracted g=2.075(5) for 8 and 40 nm samples and g=2.080(5) for the 4 nm one. Different thermal treatments of the sample showed no influence on the g factor. The magnetic anisotropy fields and g factor decrease linearly as the Si concentration increases within the D03 regime.
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