  We study single-parameter quantized charge pumping via a semiconductor
quantum dot in high magnetic fields. The quantum dot is defined between two top
gates in an AlGaAs/GaAs heterostructure. Application of an oscillating voltage
to one of the gates leads to pumped current plateaus in the gate
characteristic, corresponding to controlled transfer of integer multiples of
electrons per cycle. In a perpendicular-to-plane magnetic field the plateaus
become more pronounced indicating an improved current quantization. Current
quantization is sustained up to magnetic fields where full spin polarization of
the device can be expected.
