Measurements and Numerical Simulations of Trapped Field in a Stack of HTS Tapes

Abstract

Trapped field magnets are usually constructed on the base of bulk YBCO superconductors. However, recent achievements in the production of long-size coated conductors have opened the opportunity of using a tape stack for these applications. Better thermal conductivity, mechanical stability in high fields, and high critical current densities make such systems favorable. Moreover, the tape form of the conductor allows for organizing different spatial structures and optimizing device design. Trapped field was measured on the stack of high-temperature superconducting tapes in this work. An industrially stabilized (with copper shield) tape, which was produced by SuperOx company with GdBa 2 Cu 3 O 7-x superconductor inside, was used in experiments. The stack was made of 12-mm-diameter disk-shaped tapes, and the height was 20 layers. Magnetization was carried out by an 8-T superconducting magnet on the temperature of 77 K. To calculate the trapped field of a stack, field dependence and angular field dependence of critical current were measured on these tapes. The finite-element method was used for numerical simulations. It is shown that taking into account the magnetic field orientation in different areas of the stack leads to better agreement with the experimental measured trapped field values.