  The transversal and longitudinal resistance in the quantum Hall effect regime
was measured in a Si MOSFET sample in which a slot-gate allows one to vary the
electron density and filling factor in different parts of the sample. In case
of unequal gate voltages, the longitudinal resistances on the opposite sides of
the sample differ from each other because the originated Hall voltage
difference is added to the longitudinal voltage only on one side depending on
the gradient of the gate voltages and the direction of the external magnetic
field. After subtracting the Hall voltage difference, the increase in
longitudinal resistance is observed when electrons on the opposite sides of the
slot occupy Landau levels with different spin orientations.
