We have measured the differential resistance R = dV/dI of mesoscopic AuFe wires as a function of temperature T and dc current bias I.R(T) shows a maximum at a temperature Tm ∼1−4K, consistent with the onset of spin-glass order in these films. At temperatures T < Tm, R(I) also shows a maximum; however, R(I) is asymmetric in I, the asymmetry increasing with decreasing temperature. The asymmetry is sample specific, sensitive to the four terminal measurement configuration, and is associated with the presence of magnetic impurities in the samples.
ASJC Scopus subject areas
- General Physics and Astronomy