RESUMEN
The magnetic properties of full Heusler alloy (Co(2/3)Fe(1/3))(3+x)Si(1-x)/GaAs(001) hybrid structures grown by molecular beam epitaxy have been investigated. The magnetic moment, the coercive field and the in-plane magnetic anisotropy of (Co(2/3)Fe(1/3))(3+x)Si(1-x) films with various Si compositions (-0.46≤x≤1) are discussed. The increase in amount of Si results in a significant reduction in the cubic magnetocrystalline anisotropy constant |K(1)(eff)|. K(1)(eff) changes sign and saturates near the stoichiometric composition of Co(2)FeSi and the easy axis of the cubic component changes from the [Formula: see text] direction to the [Formula: see text] direction accordingly. However, due to the presence of a dominating uniaxial magnetic anisotropy component, the easy axis of magnetization in total is shifted to the [110] direction. The saturation magnetization of stoichiometric Co(2)FeSi films turned out to be 1250 ± 120 emu cm(-3), being equivalent to 6.1 ± 0.57 (µ(B)/formula unit (fu)). The relatively close value of magnetic moment to the theoretically expected integer value (6 µ(B)) suggests that Co(2)FeSi films could be half-metallic ferromagnets.
RESUMEN
Injection of spin polarized electrons from a metal into a semiconductor is demonstrated for a GaAs/(In,Ga)As light emitting diode covered with Fe. The circular polarization degree of the observed electroluminescence reveals a spin injection efficiency of 2%. The underlying injection mechanism is explained in terms of a tunneling process.