Demagnetization of cubic Gd-Ba-Cu-O bulk superconductor by cross-fields: measurements and 3D modelling

Abstract

Superconducting bulks, acting as high-field permanent magnets, are promising for many applications. An important effect in bulk permanent magnets is crossed-field demagnetization, which can reduce the magnetic field in superconductors due to relatively small transverse fields. Crossed-field demagnetization has not been studied in sample shapes such as rectangular prisms or cubes. This contribution presents a study based on both 3D numerical modelling and experiments. We study a cubic Gd-Ba-Cu-O bulk superconductor sample of size 6 mm magnetized by field cooling in an external field of around 1.3 T, which is later submitted to crossed-field magnetic fields of up to 164 mT. Modelling results agree with experiments, except at transverse fields 50\% or above of the initial trapped field. The current paths present a strong 3D nature. For instance, at the mid-plane perpendicular to the initial magnetizing field, the current density in this direction changes smoothly from the critical magnitude, $J_c$, at the lateral sides to zero at a certain penetration depth. This indicates a rotation of the current density with magnitude $J_c$, and hence force free effects like flux cutting are expected to play a significant role.

arXiv comment13 pages; 9 figures

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Cited by in corpus (7)

• Implementation of the H-$\varphi$ formulation in COMSOL Multiphysics for simulating the magnetization of bulk superconductors and comparison with the H-formulation
• 3D modeling of a Superconducting Dynamo-Type Flux Pump
• Coupling loss at the end connections of REBCO stacks: 2D modelling and measurement
• FFT-based solution of 2D and 3D magnetization problems in type-II superconductivity
• 3D Simulation of Superconducting Magnetic Shields and Lenses using the Fast Fourier Transform
• Time constant of the cross field demagnetization of superconducting stacks of tapes
• Modeling cross-field demagnetization of superconducting stacks and bulks for up to 100 tapes and 2 million cycles