2018

3D modeling and measurements of demagnetization of superconducting bulk and stack of tapes with magnetic cross-field ripples

Superconducting bulks and stacks could replace permanent magnets, thanks to higher trapped fields. Because of this advantage, they enhance the features of rotating machines, flywheels and magnets. In real devices like motors, there are changing magnetic fields perpendicular to the trapped field with much lower amplitude than the trapped field. These cross-filed ripples demagnetize the superconducting sample, and therefore they decrease the trapped field. In order to decrease the cross-field demagnetization, it is required to understand well this effect. For this purpose, we developed a modeling tool based on a variational method called Minimum Electro-Magnetic Entropy Production (MEMEP). We model the cross-field demagnetization of one bulk cubic sample and a stack of five superconducting tapes. The model agrees with previous works of 2D models and with the measurements.

 
Kapolka, M., Srpcic, J., Zhou, D., Ainslie, M.D., Pardo, E., and Dennis, A.R.: Demagnetization of cubic Gd-Ba-Cu-O bulk superconductor by crossed-fields: measurements and three-dimensional modeling, IEEE Trans. Applied Supercond. 28 (2018) 6801405.

Kapolka, M., Zermeno, V.M.R., Zou, S., Morande, A., Ribani, P.L., Pardo, E., and Grilli, F.: Three-dimensional modeling of the magnetization of superconducting rectangular-based bulks and tape stacks, IEEE Trans. Applied Supercond. 28 (2018) 8201206.