First-order magnetic phase transition inLaFe11.7Si1.3studied using Mössbauer spectroscopy

Abstract

Temperature and field induced magnetic phase transition in the magnetocaloric compound of ${\text{LaFe}}_{11.7}{\text{Si}}_{1.3}$ was investigated by means of M\"ossbauer spectroscopy and magnetization measurements. A coexistence of a magnetically split sextet and a paramagnetic doublet was observed in the temperature region of $\ensuremath{\sim}185--190\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ from zero-field M\"ossbauer spectra. A thermal hysteresis was verified between the heating and cooling processes that similar as observed in the thermomagnetic curves indicate that a first-order transition occurred in this compound. At the magnetic and paramagnetic phase coexisted region, the in-field M\"ossbauer measurements indicate that a span external fields from $\ensuremath{\sim}1$ to $\ensuremath{\sim}2\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ induced a magnetic phase transition as the temperature induced transformation. The in-field M\"ossbauer spectroscopy confirms that the field-induced magnetic phase transition is first-order phase transition as temperature-induced transition occurred in ${\text{LaFe}}_{11.7}{\text{Si}}_{1.3}$.