Uniaxial magnetic anisotropy in epitaxial Fe/MgO films on GaAs(001)

Magnetic and structural properties of Fe films grown on MgO buffered GaAs(001) substrates were investigated. Structural analysis using a transmission electron microscope shows that the Fe/MgO/GaAs system is fully epitaxial when MgO is grown at high temperature (~350 °C). A two-fold uniaxial magnetic anisotropy along the Fe[100]//GaAs[1̄10] was found for the epitaxial Fe/MgO/GaAs system using magnetic hysteresis loop measurements and magnetic domain imaging. However Fe grown on room temperature deposited MgO shows amorphous island morphology with discrete boundary, and no magnetic anisotropy was found.