Hydrostatic pressure study of single-crystalline UNi0.5Sb2

TL;DR

This study investigates the magnetic, thermal, and electrical properties of single-crystalline UNi0.5Sb2 under hydrostatic pressure, revealing pressure-induced shifts in transition temperature and modifications in resistivity features.

Contribution

It provides new insights into how hydrostatic pressure influences the magnetic and electronic behavior of UNi0.5Sb2, including the enhancement of TN and suppression of low-temperature resistivity features.

Findings

TN increases at ~0.76 K/kbar with pressure

Small resistivity features are suppressed under pressure

Thermal hysteresis in resistivity features increases with pressure

Abstract

We studied single-crystals of the antiferromagnetic compound UNi0.5Sb2 (TN ~ 161 K) by means of measurements of magnetic susceptibility (chi), specific heat (Cp), and electrical resistivity (rho) at ambient pressure, and resistivity under hydrostatic pressures up to 20 kbar, in the temperature range from 1.9 to 300 K. The thermal coefficient of the electrical resistivity (drho/dT) changes drastically from positive below TN to negative above, reflecting the loss of spin-disorder scattering in the ordered phase. Two small features in the rho vs T data centered near 40 and 85 K correlate well in temperature with features in the magnetic susceptibility and are consistent with other data in the literature. These features are quite hysteretic in temperature, i.e., the difference between the warming and cooling cycles are about 10 and 6 K, respectively. The effect of pressure is to raise TN at the approximate rate of 0.76 K/kbar, while progressively suppressing the amplitude of the small features in rho vs T at lower temperatures and increasing the thermal hysteresis.