The analysis of heat capacity of MnGe metallic helimagnet

TL;DR

This study decomposes the heat capacity of MnGe, revealing electronic, phononic, and spin fluctuation contributions, with findings consistent with previous estimations and experimental results.

Contribution

It introduces a method to identify spin fluctuation contributions in the heat capacity of MnGe, extending understanding of its magnetic properties.

Findings

Spin fluctuations exist across a wide temperature range in MnGe.

The spin fluctuation temperature is approximately 330 K.

Spin fluctuation amplitude is lower than phononic contributions.

Abstract

Zero-field heat capacity of metallic helimagnet MnGe was analyzed based on the results of resistivity decomposition published previously by our group for the same crystal. Current procedure allowed identifying along with ($i$) electronic ($\tilde{\gamma}$ $\approx$ 7 mJ/mol$\cdot$K$^2$) and ($ii$) phononic ($\Theta_D$ $\approx$ 350 K) components ($iii$) the additional term, caused by the presence of spin fluctuations (SFs). The last contribution was found to exist in a wide range of temperatures in both paramagnetic (PM) and magnetically ordered states. However, its amplitude appears to be significantly lower in comparison with phononic component. The obtained value of spin fluctuation temperature $\theta_{sf}$(MnGe) $\approx$ 330 K correlates well with previous estimations, as well as with results of various experiments, which predict the existence of SFs in MnGe at least up to 250 $-$ 300 K.