Multiple sign reversal of the Hall effect in electron-doped superconductor Pr$_{0.9}$LaCe$_{0.1}$CuO$_{4 \pm \delta}$ thin films

We have investigated the temperature and field dependence of the Hall resistivity of the electron-doped Pr$_{0.9}$LaCe$_{0.1}$CuO$_{4 \pm \delta}$(PLCCO) superconducting thin films($T_{c \it 0}$ =22 K). In the low magnetic field region (0.03 $\sim$ 0.1~T), a concrete triple sign reversal of the Hall resistivity $\rho_{xy}$ has been observed in the $\rho_{xy}(T)$ curve. With the increase of the magnetic field, the Hall resistivity $\rho_{xy}(T)$ suffers triple, double, single sign reversal transitions and it will be completely disappear around 4.5~T. We contribute the triple sign reversal to the competition between the hole and the electron carriers in our electron-doped samples and a fourth sign reversal may be expected in the regime of the two-band system.