Effect of the Cu stabilisation layer on the turn-to-turn contact resistance of a non-insulated REBCO winding

Although all the commercial REBCO tapes claim the stabilizer layer is pure Cu, the turn-to-turn contact resistance of coils wound from conductors sourced from different manufacturers may have a difference of more than an order of magnitude. The Cu layer in the REBCO tape with high contact resistance has a less dense microstructure and a higher impurity chemical compound such as oxide and carbide after systematically investigating. Such a phenomenon can reveal a possible new partial insulation strategy that the contact resistance could be increased without further co-winded with other materials by adjusting the microstructure and chemical composition in the Cu layer. Increasing the contact resistance with no co-winded with other materials will decrease the charging decay rate and not sacrifice the J_e value, which has application potential in the extremely high field superconducting magnets.