Conductance quantization in ferromagnetic Ni nano-constriction

The conductance in ferromagnetic Ni nano-wire is quantized in units of 2e(2)/h in the absence of magnetic field, while the units switch to e(2)/h in the magnetic field. The fractional units of 0.7e(2)/h and 1.4e(2)/h with and without magnetic field appear under the application of high bias-voltage. The spin polarization and bias-voltage play an important role in the electric conduction. (C) 2002 Elsevier Science B.V. All rights reserved.