Epitaxial growth of barium hexaferrite film on wide bandgap semiconductor 6H-SiC by molecular beam epitaxy

摘要

Epitaxial barium ferrite (BaM) films have been successfully grown by molecular beam epitaxy (MBE) for the first time on 6H silicon carbide substrates by using a 10 nm single crystalline MgO (1 1 1)//SiC(0 0 0 1) template, also grown by MBE. X-ray photoelectron spectroscopy showed that the thin MgO template in the early stages of film growth prevented the diffusion of Si into the BaM film. Background oxygen pressure (containing both O atoms and O-2, but no ionic species) is critical for determining the chemistry and surface structure of BaM. An oxygen deficient or rich environment will cause impurity phases of Fe3O4 or alpha-BaFe2O4, respectively. For BaM films grown in an optimal oxygen environment, x-ray diffraction showed a strong c-axis perpendicular to the substrate plane while the pole figure exhibited reflections consistent with epitaxial growth. Vibrating sample magnetometry showed a perpendicular magnetic anisotropy field of 16 200 Oe and a magnetization (as 4 pi M-s) of 4.1 kG.