Spin dependent tunneling device utilizing the magneto-coulomb effect

Abstract

We investigate the magneto-Coulomb effect in a single-electron tunneling transistor (SETT) with ferromagnetic leads. This effect enables us to achieve a magnetic field control, as opposed to the conventional electrical gate control of the SETT. By utilizing the sharp magnetic switching of the ferromagnetic (FM) source and drain electrodes, the magneto-Coulomb effect can attain a large magnetoconductance (MC) change in response to the applied magnetic B-field. We analyze the effect of the B-field on the effective charge Q̃ on the island, and analytically obtain the step change ΔQ̃ at the coercive field Bc of the FM leads. We also derive the optimal biasing conditions of Vg = (n ± 1/4)e/Cg and Vds ≈ V th (threshold bias). Such bias conditions ensure the maximum sensitivity (dI/dQ̃) of the SETT modulation to Q̃, and hence to the applied B-field. The magnetoconductance response of the SETT under the optimal biasing condition is numerically calculated based on the assumption of single-domain switching of the FM leads. © 2007 IEEE.