High pressure measurements of the resistivity of β-YbAlB4

Abstract

The electric resistivity ρ(T) under hydrostatic pressure up to 8 GPa was measured above 2 K using a high-quality single crystal of the Yb-based heavy fermion system β-YbAlB4. We found pressure-induced magnetic ordering above the critical pressure Pc ≈ 2.4 GPa. This phase transition temperature TM is enhanced with pressure and reaches 30 K at a pressure of 8 GPa, which is the highest transition temperature for the Yb-based heavy fermion compounds. In contrast, the resistivity is insensitive to pressure below Pc and exhibits the T-linear behavior in the temperature range between 2 and 20 K. Our results indicate that quantum criticality for β-YbAlB4 is also located near Pc in addition to the ambient pressure.