The electrical resistivity of YbCu4.5 at high pressure

We report electrical resistivity measurements of the heavy fermion compound YbCu4.5 for pressures up to 23.5 GPa. Surprisingly the temperature of the maximum of the resistivity (T-m) increases with pressure at pressures exceeding 12.5 GPa, while at low pressure T-m decreased from 20 K at ambient pressure to 4 K at 9.3 GPa. At 23.5 GPa T-m has increased to a value of 12 K. At this pressure of 23.5 GPa the resistivity was measured down to 50 mK. No trace of magnetic order, i.e. any anomaly in the resistivity behaviour has been found at this highest pressure reached.