Wydarzenia

Seminarium Międzynarodowego Laboratorium Silnych Pól Magnetycznych i Niskich Temperatur PAN

Magnetic and Levitation Properties of the Stack of HTSC Tapes in a Wide Temperature Range

Sergey Pokrovskiy, Igor Rudnev

National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, Russia

The trapped field strength of HTSC stacks were measured in the temperature range T=4-80 K and dc magnetic fields up to 8 Т. A single 12 mm by 12 mm square samples were cut from commercial (RE)BCO tape 12 mm wide and then stacked together. The number of layers in the stacks was varied from n=5 to n=250.

Trapped field strength was measured by means of Hall probe which was placed directly on the stacks surface. The dependences of remnant field strength B_rem on number of layers in the stacks at different temperature B_rem (n) as well as on temperature dependences B_rem (T) at various n were obtained. It was found that B_rem (n) dependences have a nonlinear character with a tendency to saturation for n > 60.

The maximum remnant (trapped) field was found to be more than 2.5 Т at T=4 К. The relaxation of trapped field was studied also and it was determined that the rate of relaxation processes tends to decrease with the increase in a number of tapes in the stack. The correlation between dependency B_rem (n) and dependency of magnetic levitation force measured at T=77 K at zero field cooling and field cooling regimes were found. Also we have was investigated dynamic characteristics of the levitation system based on 2G superconducting tapes stacks. It was shown high stability of the system.