Patel Dipak, Matsumoto Akiyoshi, Kumakura Hiroaki, Maeda Minoru, Kim Su-Hun, Liang Hao, Yamauchi Yusuke, Choi Seyong, Kim Jung Ho, Hossain Md Shahriar A
School of Mechanical and Mining Engineering, The University of Queensland, St Lucia, Queensland 4072, Australia.
National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
ACS Appl Mater Interfaces. 2022 Jan 19;14(2):3418-3426. doi: 10.1021/acsami.1c19581. Epub 2022 Jan 5.
A superconducting joint architecture to join unreacted carbon-doped multifilament magnesium diboride (MgB) wires with the functionality to screen external magnetic fields for magnetic resonance imaging (MRI) magnet applications is proposed. The intrinsic diamagnetic property of a superconducting MgB bulk was exploited to produce a magnetic field screening effect around the current transfer path within the joint. Unprecedentedly, the joint fabricated using this novel architecture was able to screen magnetic fields up to 1.5 T at 20 K and up to 2 T at 15 K and thereby almost nullified the effect of the applied magnetic field by maintaining a constant critical current (). The joint showed an of 30.8 A in 1.5 T at 20 K and an ultralow resistance of about 3.32 × 10 Ω at 20 K in a self-field. The magnetic field screening effect shown by the MgB joint is expected to be extremely valuable for MRI magnet applications, where the of the joints is lower than the of the connected MgB wires in a given magnetic field and temperature.
提出了一种超导接头结构，用于连接未反应的碳掺杂多丝二硼化镁（MgB）导线，该结构具有为磁共振成像（MRI）磁体应用屏蔽外部磁场的功能。利用超导MgB块体的固有抗磁特性，在接头内的电流传输路径周围产生磁场屏蔽效应。前所未有的是，使用这种新型结构制造的接头在20 K时能够屏蔽高达1.5 T的磁场，在15 K时能够屏蔽高达2 T的磁场，从而通过保持恒定的临界电流（）几乎消除了外加磁场的影响。该接头在20 K的1.5 T磁场中显示出30.8 A的临界电流，在自场中20 K时具有约3.32×10Ω的超低电阻。MgB接头所显示的磁场屏蔽效应预计对MRI磁体应用极具价值，在给定磁场和温度下，接头的临界电流低于所连接的MgB导线的临界电流。
