The study of MgB₂/BN/MgB₂ trilayer films

Highlights: • We fabricate MgB₂/BN/MgB₂ trilayer films. • We study the films by XPS, TEM, SEM, XRD and MPMS. • Both bottom MgB₂ film and the BN film are epitaxial and smooth. • Bottom MgB₂ film is not deteriorated after growing the BN film. - Abstract: MgB₂/BN/MgB₂ trilayer films have been fabricated by using hybrid physical–chemical vapor deposition (HPCVD) method for the MgB₂ layers and chemical vapor deposition (CVD) method for the BN layers in the same reactor. The films are studied by X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD) and magnetization measurements. These test outcomes indicate the trilayer films are grown without deteriorating the superconductivity of MgB₂ films. Our results show that it is feasible to grow MgB₂/BN/MgB₂ trilayer films in the same reactor sequentially, which has the advantage of reducing contamination during the growth. This therefore opens the door for fabricating all-MgB₂ Josephson junctions by using the BN film as the insulating layer.