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The effects of Ga composition (x) on soft and high-frequency magnetic properties of 10-nm-thick B-doped Fe–Ga (Fe85.1−xGaxB14.9) thin films were investigated. A uniaxial magnetic anisotropy appeared regardless of the Ga composition. The damping constant values and magnetic inhomogeneous broadening at a zero frequency were much lower than those of the Fe–Ga polycrystalline film for all Ga compositions. These results indicate that adding B atoms to Fe–Ga thin films improves the soft and high-frequency magnetic properties of these films and suggest that Fe–Ga–B thin films are candidate magnetostrictive materials for high-frequency devices.

We have investigated InAs deep quantum well structures (InAs DQWs) made from InAs/A1GaAsSb materials on GaAs substrates by molecular beam epitaxy (MBE). In the InAs DQWs, AlGaAsSb layers are lattice-matched to InAs. Using reflection high-energy electron diffraction (RHEED) linescan image analysis, we show that AlGaAsSb on GaAs surfaces quickly relaxes within 3 to 7 monolayers (MLs). The initial stages of AlxGa1-xAsSb (0≤x≤0.5) growth on GaAs (100) substrates and InAs growth on AlGaAsSb layers have been investigated by atomic force microscopy. The ridgeline shapes of AlGaAsSb are observed at the initial stage on GaAs surfaces. In the interface of the InAs/AIGaAsSb, two-dimensional (2D) growth of InAs has been observed. With a thin buffer layer of 600 nm AlGaAsSb, we have achieved very high electron mobilities of more than 32000 cm2/V-s at room temperature.