  The induced motion of a magnetic vortex in a micron-sized ferromagnetic disk
due to the DC current injection is studied by measuring planar Hall effect. The
DC current injection is found to induce the spin torque that sweeps the vortex
out of the disk at the critical current while bias magnetic field are applied.
The current-induced vortex core displacement deduced from the change in planar
Hall resistance is quantitatively consistent with theoretical prediction. Peak
structures similar to those originated from spin wave excitations are observed
in the differential planar Hall resistance curve.
