Differential conductance anomaly in ferromagnetic Ni nanocontacts

The current-voltage characteristics of ferromagnetic Ni and diamagnetic Cu nanocontacts was investigated by using break-junction technique. The I-V curve of Ni nanocontacts exhibits a non-linear behavior, and it is due to the spin polarization. In contrast, the current flowing Cu nanocontact is proportional to bias voltage up to 600 mV.