Published online by Cambridge University Press: 15 February 2011
We report the studies of the Hall effect and magnetic properties in La0.5Ca0.5CoO3 thin films and ceramics. We use the local Hall probe and SQUID magnetometers to measure the magnetization M of the samples. Both below and above the Curie temperature, the Hall resistivity pxy(H) is shown to be proportional to M(H) (H is the applied magnetic field). Thus, our results provide convincing evidence for the anomalous Hall effect in these cobaltites. The value of the anomalous Hall coefficient Rs in La0.5Ca0.5CoO3 significantly exceeds those of other known single-phase ferromagnetic metals. We suggest that the coexistence of high- and low-spin configurations in the perovskite cobaltites, which gives rise to magnetic percolation behavior in La1-xCax.CoO3,may be responsible for the giant Ra.