Einfluß von Anlaßbehandlungen auf Restwiderstand und Magnetfeldabhängigkeit des elektrischen Widerstandes von Niob bei 4,2 K.

Measurements of the residual resistivity of Nb are usually carried out in longitudinal magnetic fields > H ≈4.7 kOe. After annealing of Nb wires in helium or vacuum of 5·10 Torr a shift of the transition to normal conductivity towards higher fields (up to 9.3 kOe) was observed. This increase of the critical field is most likely caused by changes in the surface of the samples due to the annealing treatments. [ABSTRACT FROM AUTHOR]