High Pressure Measurements of the Resistivity of $\beta$-YbAlB$_4$

TL;DR

This study investigates how hydrostatic pressure affects the resistivity and magnetic ordering in the heavy fermion compound $eta$-YbAlB$_4$, revealing pressure-induced magnetic phase transition and quantum criticality.

Contribution

It provides the first detailed resistivity measurements under high pressure up to 8 GPa on $eta$-YbAlB$_4$, identifying a pressure-induced magnetic phase transition and quantum critical behavior.

Findings

Magnetic ordering appears above 2.4 GPa with transition temperature reaching 30 K at 8 GPa.

Resistivity remains pressure-insensitive below critical pressure and shows T-linear behavior.

Quantum criticality persists near the critical pressure, indicating complex magnetic interactions.

Abstract

The electric resistivity $\rho(T)$ 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 $\beta$-YbAlB$_4$. We found pressure-induced magnetic ordering above the critical pressure $P_{\rm c} \approx $ 2.4 GPa. This phase transition temperature $T_M$ 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 $P_c$ and exhibits the $T$-linear behavior in the temperature range between 2 and 20 K. Our results indicate that quantum criticality for $\beta$-YbAlB$_4$ is also located near $P_{\rm c}$ in addition to the ambient pressure.