Contact Resistance Between REBCO Coated Conductors in the Presence of a V2O3 Inter-Layer

We report a study of the contact resistance between commercial Cu-stabilized REBCO tapes coated with V
₂
O
₃
, which is a functional material that passes through a metal-to-insulator transition at cryogenic temperatures. We prove that a simple dip coating technique, potentially scalable to coat long-length conductors, allows the deposition of ∼10-μm-thick V
₂
O
₃
layers. We find that the contact resistance between the REBCO tapes is mainly determined by the properties of the V
₂
O
₃
layer and that it varies by more than 8 orders of magnitude from 10 K to room temperature. Based on our experimental results and on previous studies [Denis Markiewicz et al., 2019], we deduce that an effective quench propagation may take place in REBCO pancake coils when the hot spot temperature is in the range 135 K–175 K, depending on the V
₂
O
₃
layer thickness. Because of the metal-to-insulator transition of the V
₂
O
₃
, the contact resistance rapidly increases at lower temperatures, assuming values comparable with those of insulated coils. In a general perspective, the results of this research can help magnet designers to assess the role of metal-to-insulator-transition materials for future REBCO-based magnets.