On electron transport in ZrB12, ZrB2, and MgB2 in normal state

We report on measurements of the temperature dependence of resistivity, rho(T), for single-crystal samples of ZrB12, ZrB2, and polycrystalline samples of MgB2. It is shown that the cluster compound ZrB12 behaves as a simple metal in the normal state, with a typical Bloch-Gruneisen rho(T) dependence. However, the resistive Debye temperature, T-R = 300 K, is three times smaller than T-D obtained from specific heat data. We observe the T-2 term in rho(T) of all these borides, which could be interpreted as an indication of strong electron-electron interaction. (C) 2004 MAIK "Nauka / Interperiodica".