RESISTIVITY AND THERMOELECTRIC-POWER OF YBCU4.5 UNDER VERY HIGH-PRESSURE

Transport properties of YbCU4.5 at zero pressure and under high pressu re are reported The resistivity is strongly perturbed by the disorder of the crystallographic structure, showing notably high residual resis tivity and anisotropy at low temperature. Several samples have been me asured at zero pressure and results are dominated by the Kondo effect: resistivity anomaly and giant thermoelectric power. Crystal field eff ect is taken into consideration to account for resistivity data. Under pressure, the decrease of the Kondo temperature have been observed wi th two experiments, up to 17 and 93 kbar. The possible appearance of a magnetic ground state under pressure is discussed.