Low Temperature Resistivity of the Rare Earth Diborides (Er, Ho, Tm)B_2

摘要

The discovery of superconductivity in MgB_2 sparked much interest in the diborides and led to further discoveries in this class of materials. Attention has focussed on the transitions metal diborides and the rare-earth diborides have remained sparsely investigated. Here we present electrical transport in polycrys-talline samples of ErB_2, TmB_2 and HoB_2 as a function of temperature down to 0.1 K. Particularly interesting is the large difference in the temperature dependence of resistivity, above and below the clear magnetic ordering temperature of 13.8, 9 and 7.5 K for ErB_2, HoB_2 and TmB_2 respectively.