Mechanical properties and field trapping ability of bulk superconductors with resin impregnation

We have studied the mechanical properties of Y-Ba-Cu-O rods with and without resin impregnation using a Vickers indenter test. The respective stress intensity factor (K_c) values of YBCO superconductors with and without resin impregnation were 0.84 MPa m^1/2 and 0.69 MPa m^1/2. This shows that resin impregnation is effective in improving the fracture toughness. We also performed trapped-field measurements for YBCO bulk superconductors 24 mm in diameter with and without resin impregnation at 30 K. The samples without resin impregnation could trap 10.17 T at 37 K but cracked at lower temperatures. In contrast, the sample with resin impregnation could stably trap an extremely high field of 14.89 T at 30 K, reflecting the improvement of mechanical properties.