STRUCTURE AND ELECTRICAL-RESISTIVITY OF THE HEAVY-FERMION COMPOUND CECU5AU

The crystal structure of CeCu5Au determined at room temperature is ort horhombic with space group Pnma (No. 62). The lattice constants are a = 8.2455 (4), b = 5.0866 (3) and c = 10.3659 (5) angstrom with V = 434 .76 (7) angstrom3 and four formula units per unit cell. Four-circle di ffractometry shows that CeCU5Au is an ordered intermetallic phase, iso morphous with CeCu6, with the Au atoms exclusively occupying the Cu(2) positions of the CeCU6 structure. Measurements of the electrical resi stivity of CeCu5Au at low temperatures yield a residual resistivity sm aller than that of single crystals of CeCu5.5Au0.5 by a factor of four , in line with the fact that CeCU5Au is a stoichiometric compound. The temperature dependence of the resistivity indicates magnetic ordering as found previously for CeCu6-xAux with 0.1 < x < 1.