The preparation of cylindrical MgB2 films on stainless steel by HPCVD for magnetic shielding

HTC 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 HTC SQUID is limited because lack of proper magnetic shielding. Superconducting magnetic shielding is an efficient way for HTC SQUID. In this work, we fabricate MgB2 thick film on a stainless steel cylinder using HPCVD to make a preliminary attempt for SMS with MgB2 films. High quality MgB2 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 × 106 A⋅cm−2 at 10 K and 4.6 × 106 A⋅cm−2 at 20 K, which is comparable with the planar films. The shielding effectiveness of the cylindrical MgB2 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 MgB2 film as magnetic shielding.