Growth and magnetic properties of epitaxial MnAs/NiAs/MnAs heterostructures grown on exact GaAs(1 1 1)B substrates

We have investigated the growth, structural characterization and magnetic properties of epitaxial MnAs/NiAs/MnAs heterostructures grown on exact GaAs(1 1 1)B substrates by molecular beam epitaxy. Reflection high energy electron diffraction observation during the growth and cross-sectional transmission electron microscopy analysis revealed that the epitaxial orientation of [0 0 0 1]MnAs//[0 0 0 1]NiAs// [ 1 ¯ 1 ¯ 1 ¯ ] GaAs is maintained throughout the growth with atomically abrupt heterointerfaces. The magnetization loops of the heterostructures show double-step features when the thickness of the NiAs interlayer was more than 8 nm. The magnetic properties, such as the temperature dependence of magnetization, were sensitive to the growth conditions, which mainly results from the crystalline quality of the top MnAs layer.