Hall effect and charge carrier density in Eu1−Ca B6 (x=0.2, 0.4, 0.6, and 0.9)

Abstract Temperature and field dependent Hall resistivity ρ H ( T ) has been measured for the single crystals of Eu 1− x Ca x B 6 ( x =0.2, 0.4, 0.6, and 0.9). The effective charge carrier density n eff ( T , H ) and Hall mobility μ H ( T ) were derived from the ρ H ( T ). A large variation in the n eff ( T , H ) for x =0.2 and 0.4 compounds was found, while relatively small change for x =0.6 and 0.9 compounds. Analysis of the μ H , based on a small polaronic model, showed that the carrier transport is dominated by the activation of electrons in small polarons. This polaronic scenario of the transport is consistent with the variation of n eff ( T , H ).