Pressure-Temperature Phase Diagram of Golden SmS

TL;DR

This study constructs a detailed pressure-temperature phase diagram of golden SmS, revealing crossover and magnetic transition lines, and suggests a valence jump at the antiferromagnetic boundary, advancing understanding of its phase behavior.

Contribution

The paper provides the first detailed pressure-temperature phase diagram of golden SmS, identifying crossover and magnetic transition lines and proposing a valence jump at the antiferromagnetic boundary.

Findings

Identified a crossover line dividing paramagnetic phases.

Detected second-order and first-order Neel transitions.

Suggested a valence jump at the antiferromagnetic boundary.

Abstract

We measured the thermal expansion of the valence fluctuating phase of SmS (golden SmS) to construct a pressure vs temperature phase diagram. The obtained phase diagram is characterized by three lines. One is a crossover line that divides the paramagnetic phase into two regions. The other two lines correspond to a second-order Neel transition and a first-order Neel transition. The crossover line appears to emerge from a tricritical point that separates the first-order Neel transition from the second-order one. We argue that a valence jump occurs at the border of antiferromagnetism.