Pressure-tuned First-order Phase Transition and Accompanying Resistivity Anomaly in CeZn_{1-\delta}Sb_{2}

TL;DR

This study investigates pressure-induced phase transitions and resistivity anomalies in CeZn_{1-b}Sb_{2}, revealing a weakly first-order transition with critical fluctuations and superzone gap effects.

Contribution

It provides the first detailed analysis of pressure-tuned first-order phase transitions and resistivity anomalies in CeZn_{1-b}Sb_{2}, linking experimental observations to the Suzaki-Mori theory.

Findings

Resistivity changes from Fisher-Langer to Suzaki-Mori type near 17 kbar.

The resistivity anomaly shows thermal hysteresis, indicating a weakly first-order transition.

Negative divergence in d ho/dT suggests enhanced critical fluctuations.

Abstract

The Kondo lattice system CeZn_{0.66}Sb_{2} is studied by the electrical resistivity and ac magnetic susceptibility measurements at several pressures. At P=0 kbar, ferromagnetic and antiferromagnetic transitions appear at 3.6 and 0.8 K, respectively. The electrical resistivity at T_N dramatically changes from the Fisher-Langer type (ferromagnetic like) to the Suzaki-Mori type near 17 kbar, i.e., from a positive divergence to a negative divergence in the temperature derivative of the resistivity. The pressure-induced SM type anomaly, which shows thermal hysteresis, is easily suppressed by small magnetic field (1.9 kOe for 19.8 kbar), indicating a weakly first-order nature of the transition. By subtracting a low-pressure data set, we directly compare the resistivity anomaly with the SM theory without any assumption on backgrounds, where the negative divergence in d\rho/dT is ascribed to enhanced critical fluctuations in the presence of superzone gaps.