New resistance anomaly in the superconducting fluctuation region of disordered Cu-Zr alloys with dilute magnetic impurities

In disordered superconducting Cu-Zr alloys with dilute magnetic impurities, we have observed a new type of resistance anomaly which gives rise to strongly increased scattering of conduction electrons in a narrow temperature range above ${\mathit{T}}_{\mathit{c}}$ and appears to be due to interaction between superconducting fluctuations and spin. For a given level of impurities this phenomenon is peaked around ${\mathrm{Cu}}_{50}$ ${\mathrm{Zr}}_{50}$, but is observable from 36 to 60 at.% Zr. When the Cr impurity concentration is varied in ${\mathrm{Cu}}_{50}$ ${\mathrm{Zr}}_{50}$, a resistance peak can be observed for 100–600 ppm Cr with a maximum peak height of about 6% of the measured resistance. The effect is destroyed by a magnetic field of some tenths of a tesla.