Trapped fields up to 2 T in a 12 mm square stack of commercial superconducting tape using pulsed field magnetization

Abstract

The ability of superconductors to sustain persistent currents has been well exploited with (RE)BCO superconducting bulks, which can be magnetized to form a compact source of high magnetic field. However, thin films can also sustain persistent currents, which can be utilized by stacking them in layers to create a type of composite bulk. Such a stack is capable of trapping higher fields than a bulk, as reported in this paper. 12 mm wide, 55 µm thick commercial (RE)BCO tape from Superpower Inc was cut into 12 mm by 12 mm squares, stacked together and magnetized at temperatures between 10 and 77.4 K using a sequence of pulsed magnetic fields. The results are compared to a commercial 14 mm diameter YBCO bulk, showing that the stack of tapes outperformed the bulk at temperatures below approximately 60 K. Particularly high trapped fields were achieved below 50 K, with a maximum of 2.0 T at 10 K measured 0.8 mm from the stack surface. The maximum trapped field possible for a stack of tapes increases significantly with decreasing temperature down to 10 K, rather than saturating at a higher temperature as in the case of a bulk, due to superior thermal stability. The J c , thermal and mechanical properties of commercial (RE)BCO tapes give them great potential for use as trapped field magnets activated by pulsed magnetic fields.

Simulation of magnetization and levitation characteristics of HTS tape stacks

“…We performed comparison of the calculated distributions of the magnetic flux trapped by the stacks with the experimental dependences of Hall magnetometry measurements. Scanning height was 0.7 mm [3]. The calculated data are in consistence with the experimental data for the samples of circular shape (Figure 4 (a)) and the square shape (Figure 4,(b)).…”

Vortex shaking study of REBCO tape with consideration of anisotropic characteristics

“…For both applications, it is crucial and significant to study the vortex shaking effect of superconducting stacks made of REBCO. REBCO stacks have been reported trapped magnetic field higher than 7 T at 4.2 K [1,2], making them promising candidate for high power density rotating machines. In the operation of rotating machines, the superconducting stacks are subjected to alternating external magnetic field, which may lead to the decay of the trapped magnetic field and results in lower performance of the machines.…”

Crossed-magnetic-field experiments on stacked second generation superconducting tapes: Reduction of the demagnetization effects

“…By using second generation (2G)-HTS tapes, recently, Patel et al have reported a series of field cooling magnetization experiments, 3,4 achieving trapped magnetic fields up to 7.34 T at 4.2 K in the middle point between two 12 mm square stacks, each made of 120 layers of 2G-HTS tapes. This surprisingly high value for the trapped magnetic field given the small size of the stack together with the commercial availability of the tapes, almost uniform physical properties in long lengths, and considerably higher mechanical strength compared with the one of superconducting bulks, 4 makes the stack configuration of 2G-HTS tapes an ideal candidate for practical applications where strong magnets are required.…”