Tricritical behavior in MnSi at nearly hydrostatic pressure

TL;DR

This study investigates the phase transition behavior of MnSi under nearly hydrostatic pressure, revealing a tricritical point at lower pressure and higher temperature than previously reported, thus refining understanding of its magnetic phase diagram.

Contribution

The paper provides new experimental evidence locating the tricritical point of MnSi at lower pressure and higher temperature, challenging earlier assumptions and constraining theoretical models.

Findings

Tricritical point at ~0.355 GPa and ~25.2 K

Phase transition behavior differs from previous reports

Results impose new constraints on the origin of the tricritical point

Abstract

AC magnetic susceptibility of a single crystal of MnSi was measured along the ferromagnetic phase-transition line up to a pressure of 0.8 GPa created by compressed helium. The results show that the tricritical point is situated at much lower pressure and at significantly higher temperature (Ptr~0.355 GPa, Ttr~25.2 K) than was reported previously (~1.2 GPa,~12 K). These new observations put certain constraints on the origin of the tricritical point in MnSi.