# Physical properties of (Mn 0.85 Fe 0.15) Si along the critical trajectory

## TL;DR

This study investigates the magnetic, thermal, and structural properties of Mn 0.85 Fe 0.15 Si, revealing no second-order phase transition and highlighting its proximity to a quantum critical point with persistent helical fluctuations.

## Contribution

It provides experimental insights into the critical behavior and fluctuation effects in Fe-doped MnSi near the quantum critical point.

## Key findings

- No thermodynamic evidence of second-order phase transition.
- Approaching quantum critical point at low temperatures.
- Presence of helical fluctuations near the phase transition line.

## Abstract

We report results of studying the magnetization, specific heat and thermal expansion of a single crystal with nominal composition Mn 0.85 Fe 0.15 Si . We found no thermodynamic evidences in favor a second order phase transition in the 15 % Fe substituted MnSi. The trajectory corresponding to the present composition of (MnFe)Si is a critical one, i.e. approaching quantum critical point at lowering temperature, but some properties may feel the cloud of helical fluctuations bordering the phase transition line.