MODEL CALCULATION FOR SPIN-POLARIZED TUNNELING

We present a model calculation for spin-polarized tunneling at bias voltages in the range of volts. The electrodes are represented by semi-infinite potential wells. Spin and energy distribution of the electrons is taken into consideration by spin-resolved density of states (SDOS). The tunneling probability as a function of energy and relative spin orientation is calculated in a one-dimensional geometry using a rectangular potential barrier. On the basis of this simple model we predict that the resulting dependence of the effective polarization of the junction upon the bias voltage originates mainly from the structure in the SDOS. Finally we apply the model to the CrO2-Cr(001) junction using theoretical SDOS given in the literature for both materials.