Epitaxial ferromagnetic Fe_3Si on GaAs(111)A with atomically smooth surface and interface

摘要

Single crystal ferromagnetic Fe_3Si(111) films were grown epitaxially on GaAs(111)A by molecular beam epitaxy. These hetero-structures possess extremely low surface roughness of 1.3 A and inter-facial roughness of 1.9 A, measured by in-situ scanning tunneling microscope and X-ray reflectivity analyses, respectively, showing superior film quality, comparing to those attained on GaAs(001) in previous publications. The atomically smooth interface was revealed by the atomic-resolution Z (atomic number)-contrast scanning transmission electron microscopy (STEM) images using the correction of spherical aberration (Cs)-corrected electron probe. Excellent crystallinity and perfect lattice match were both confirmed by high resolution x-ray diffraction. Measurements of magnetic property for the Fe_3Si/GaAs(111) yielded a saturation moment of 990 emu/cm~3 with a small coercive field ≤ 1 Oe at room temperature.