Normal and anomalous Hall effect in CeSb and CeBi

Anomalous behavior of Hall constant and magnetoresistance in CeSb and CeBi under high magnetic field and high pressure is studied critically. At first, anomalous held dependence in the reference systems LaSb and LaBi is investigated based on the three band model in which two kinds of electrons are treated independently and it is concluded that the anomalous behavior is due to a small deviation from the stoicheometry, which is enhanced by a large mobility. In CeSb without pressure. no anomalous Hall effect is observed even in the ferromagnetic state. On the other hand, the normal Hall constant in CeSb and CeBi shows strong electron scattering in the whole temperature region confirming the model that the electrons also substantially contribute to the Gamma(8) Kondo state. To study the anomalous Hall effect under high pressure and high magnetic field, general equations for anomalous Hall effect under high magnetic field are derived, and the anomalous Hall effect is identified to exit in the region in which a kind of magnetic polaron crystallization is thought to occur causing a sharp increase in resistivity. This is thought to be due to the direct 4f motion, similar to those in the mixed valence regime and the intermediate region in CeP and CeAs.