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

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.