Growth and characterization of single crystalline NiMnSb thin films and epitaxial NiMnSb/MgO/NiMnSb(001) trilayers

NiMnSb(001) high-quality epitaxial thin films have been prepared by molecular-beam epitaxy. The growth and morphology of the films have been extensively studied using electron diffraction and scanning tunneling microscopy. We report the presence of various surface structures on the free NiMnSb(001) surface. The structural properties of the prepared single-crystalline NiMnSb films have been analyzed by transmission electron microscopy and x-ray absorption. The typical C1b structure is observed at a large scale with a very good chemical ordering in the unit cell. The magnetic properties have been investigated by x-ray magnetic circular dichroism and a superconducting quantum interferometer device and are compatible with the predicted half-metallic character. These NiMnSb layers have been integrated in single-crystalline NiMnSb/MgO/NiMnSb heterostructures for preparation of magnetic tunnel junctions with half-metallic electrodes.