Anomalous charge transport in RB12 (R = Ho, Er, Tm, Lu)

High precision measurements of Hall R-H(T) and Seebeck S(T) coefficients have been carried out for the first time on single crystals of rare earth dodecaborides RB12 (R = Ho, Er, Tm, Lu) at temperatures 1.8-300 K. Low temperature anomalies detected on the temperature dependencies of R-H(T) and S(T) are associated with antiferromagnetic phase transitions in HoB12, ErB12 and TmB12 compounds. The observed discrepancy between the change of charge carriers' mobility and de-Gennes factor (g-1)(2) J(J+1) (J-angular momentum of the 4f shell) in the set of HoB12-TmB12 allows us to conclude about the appreciable influence of spin fluctuations on the charge transport in these compounds with B-12 atomic clusters. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim