Measurement of <f>V–I</f> characteristics of commercial multifilamentary NbTi wires

The voltage–current characteristics of commercial multifilamentary NbTi wires have been examined in the magnetic fields from 0 to 10 T. The measurements were performed using a specimen holder made of a fiberglass epoxy cylinder of 50 mm in diameter. The specimens of 300 mm length were spirally wound on it and the normal-state transition was measured over the central 150 mm of the specimen. The results show that in the field above 3 T the <f>n</f>-values determined from the <f>V–I</f> traces for the electric field higher than 10 μV/m increase with decreasing field, but below 2 T the <f>n</f>-values begin to decrease and take a minimum at about 0.5 T. [Copyright &y& Elsevier]