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MgB 2 /BN/MgB 2 trilayer films have been fabricated by using hybrid physical–chemical vapor deposition (HPCVD) method for the MgB 2 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 MgB 2 films. Our results show that it is feasible to grow MgB 2 /BN/MgB 2 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-MgB 2 Josephson junctions by using the BN film as the insulating layer. [ABSTRACT FROM AUTHOR]

Demonstrates that high pressure chemical vapor deposition (HPCVD) is an effective and efficient approach to the synthesis of thick magnesium boride films over the stainless substrate. X-ray diffraction pattern of magnesium boride film grown on the stainless steel substrate; Deposition rate of the film; Tenacity and the bonding strength of the film to the substrate.

High quality single-crystal magnesium diboride (MgB2) nanowires with lengths exceeding 10 μm were successfully synthesized by hybrid physical chemical vapor deposition. The magnetization and electrical transport properties of single-crystal MgB2 nanowires (NWs) were measured. The superconducting transition temperature of the NWs was 37 K, as confirmed by magnetization measurements. The disordered behavior of the nanowires was observed by four-terminal current–voltage characteristic measurements of an individual NW from T = 10 to 300 K. The temperature-dependent resistivity curves for seven NWs collapsed into a universal curve described by the variable range hopping model, showing intrinsic nonmetallic transport properties. This implies that the granular superconducting defect states are critical to the superconductivity of the individual MgB2 NWs. [ABSTRACT FROM AUTHOR]

HT C SQUID has a great potential in ultra-weak magnetic signal detections due to its advantages of energy saving and volume reduction of the overall system, including the cryogenics. However, the application of HT C SQUID is limited because lack of proper magnetic shielding. Superconducting magnetic shielding is an efficient way for HT C SQUID. In this work, we fabricate MgB 2 thick film on a stainless steel cylinder using HPCVD to make a preliminary attempt for SMS with MgB 2 films. High quality MgB 2 film is deposited on the inner side of a hollowed cylinder. The transition temperature of the film is 37.5 K, and the critical current density is 7.6 × 10 6 A⋅cm −2 at 10 K and 4.6 × 10 6 A⋅cm −2 at 20 K, which is comparable with the planar films. The shielding effectiveness of the cylindrical MgB 2 film is numerical simulated. Height and thickness of the cylindrical magnetic shielding designed according to the simulation result was calculated and a corresponding shielding effectiveness of 65 dB is obtained. The numerical result shows the feasibility of using MgB 2 film as magnetic shielding. [ABSTRACT FROM AUTHOR]

MgB 2 superconducting films, whose thicknesses range from 10 nm to 8 µm, have been fabricated on SiC substrates by hybrid physical–chemical vapor deposition (HPCVD) method. It is the first time that the T c and the J c of MgB 2 films are studied on such a large scale. It is found that with the increasing of thickness, T c elevates first and then keeps roughly stable except for some slight fluctuations, while J c (5 K, 0 T) experiences a sharp increase followed by a relatively slow fall. The maximum J c (5 K, 0 T) = 2.3 × 10 8 A cm −2 is obtained for 100 nm films, which is the experimental evidence for preparing high-quality MgB 2 films by HPCVD method. Thus, this work may provide guidance on choosing the suitable thickness for applications. Meanwhile, the films prepared by us cover ultrathin films, thin films and thick films, so the study on them will bring a comprehensive understanding of MgB 2 films. [ABSTRACT FROM AUTHOR]

200 nm Ni film is coated on 25 μm thick Mo foil, and graphene is grown on the Ni–Mo system by CVD method. After the annealing process of CVD, the Ni/Mo bilayer transforms into Ni–Mo alloy, then we have successfully fabricated MgB 2 films on graphene/Ni–Mo alloy system via the hybrid physical–chemical vapor deposition (HPCVD) technique. The transition temperature T c onset is 38.25 K with a corresponding transition width of 0.75 K. The average thickness of MgB 2 films is 200 nm (25% concentration B 2 H 6 ). The critical current density derives from the magnetization measurement at 5 K is, j c (5 K, 0 T) = 9.6 × 10 6 A/cm 2 . We can easily deposite MgB 2 on graphene/Ni–Mo alloy system with a lower B 2 H 6 concentration and less gas flow, which lays a good foundation for depositing MgB 2 thick films. The graphene in this system is multilayer and with defects, it may act like an intermediary film for the growth of MgB 2 , or a carbon-doping source. [ABSTRACT FROM AUTHOR]

The article presents a study which demonstrates the magnesium diboride (MgB2) superconducting whiskers synthesized by hybrid physical-chemical vapor deposition (HPCVD). The HPCVD setups that were employed in this experiment were quartz chamber with induction heating and stainless steel chamber with resistivity heating. A scanning electron microscope was used to analyze the morphologies of the whiskers. It has observed an onset temperature of 39 K.