Magnetic domain dependent quantum transport through a ferromagnetic dot embedded in a semiconductor quantum wire

Two unique quantum transport features, a clear appearance of Coulomb oscill ations and a narrowing of Coulomb gap, are observed in an embedded ferromag net (Ni) dot in a semiconductor wire after magnetic field application. Magn etic force microscopy analysis suggests the existence of a domain wall insi de the dot before the field application, but it disappears after the field application forming a single domain in the dot. If we establish a transport model by assuming that the domain wall plays the role of a "resistive barr ier," we can explain those unique transport features in terms of "Coulomb b lockade effects modified by domain dynamics." [S0031-9007(98)07816-8].