We present a phenomenological analysis of the magnetoelastic properties of CeCo0.85Fe0.15Si at temperatures close to the N\'eel transition temperature TN. Using a Landau functional we provide a qualitative description of the thermal expansion, magnetostriction, magnetization and specific heat data. We show that the available experimental results [Journal of Physics: Condensed Matter 28 346003 (2016)] are consistent with the presence of a structural transition at Ts≳TN and a strong magnetoelastic coupling. The magnetoelastic coupling presents a Janus-faced effect: while the structural transition is shifted to higher temperatures as the magnetic field is increased, the resulting striction at low temperatures decreases. The strong magnetoelastic coupling and the proximity of the structural transition to the onset temperature for magnetic fluctuations, suggest that the transition could be an analogue of the tetragonal to orthorhombic observed in Fe-based pcnictides.
@article{arxiv.1802.02600,
title = {Landau theory for magnetic and structural transitions in CeCo$_{0.85}$Fe$_{0.15}$Si},
author = {William Gabriel Carreras Oropesa and Víctor F. Correa and Julián G. Sereni and Daniel J. García and Pablo S. Cornaglia},
journal= {arXiv preprint arXiv:1802.02600},
year = {2018}
}