  Slow magnetization relaxation processes are an important time-dependent
property of many magnetic materials. We show that magnetotransport measurements
based on a well-established current-reversal method can be utilized to
implement a simple and robust screening scheme for such relaxation processes.
We demonstrate our approach considering the anomalous Hall effect in a
Pt/Co/AlOx trilayer model system, and then explore relaxation in {\tau} -MnAl
films. Compared to magnetotransport experiments based on ac lock-in techniques,
we find that the dc current-reversal method is particulary sensitive to
relaxation processes with relaxation time scales on the order of seconds,
comparable to the current-reversal measurement time scales.
