Conductance fluctuations in the presence of spin scattering

Electron transport through disordered systems that include spin scatterers is studied numerically. We consider three kinds of magnetic impurities: the Ising, the XY, and the Heisenberg. By extending the transfer matrix method to include the spin degree of freedom, the two terminal conductance is calculated. The variance of conductance is halved as the number of spin components of the magnetic impurities increases. Application of the Zeeman field in the lead causes a further halving of the variance under certain conditions.