Peculiar behavior of the electrical resistivity of MnSi at the ferromagnetic phase transition

TL;DR

This study investigates the peculiar features of electrical resistivity in MnSi during its ferromagnetic phase transition, revealing pressure-dependent fine structures that suggest complex magnetic behavior near a tricritical point.

Contribution

It provides new insights into the pressure-dependent resistivity behavior of MnSi and identifies a pressure range where the transition's characteristics change.

Findings

Peaks in resistivity coefficient at the transition line

Fine structure with a shoulder at ~0.5 K above the peak at low pressures

Disappearance of the fine structure above ~0.35 GPa

Abstract

The electrical resistivity of a single crystal of MnSi was measured across its ferromagnetic phase transition line at ambient and high pressures. Sharp peaks of the temperature coefficient of resistivity characterize the transition line. Analysis of these data shows that at pressures to ~0.35 GPa these peaks have fine structure, revealing a shoulder at ~ 0.5 K above the peak. It is symptomatic that this structure disappears at pressures higher than ~0.35 GPa, which was identified earlier as a tricritical point