Fermi-liquid instability of CeRhSi near a pressure-induced quantum phase transition

The electrical resistivity of single crystalline CeRhSi has been measured at high pressure up to 8 GPa, and low temperature down to 2.0 K for the current along the a and c axes. Two magnetic phase transitions TN=35 K and TN=24 K at ambient pressure were observed as a function of pressure. It is found that both transitions TN and TN are suppressed by applying pressure and disappear near the critical pressure at PC∼1.0 GPa and PC∼0.6 GPa, respectively. The transition for TN is second order and the one for TN is first order. The resistivity shows T dependence at low temperature in a wide pressure range from ambient pressure up to 8 GPa, indicating that a Fermi liquid state still exists near P and P. According to the comparison between the coefficient of T term and the Sommerfeld coefficient γ, however, it is suggested that the enhancement of many-body dynamical effect occurs near the critical pressure P∼1.0 GPa. These results are discussed on the basis of the pressure-induced quantum phase transition. © 2003 The American Physical Society.