Thermomagnetic history effects in SmMn$_2$Ge$_2$

TL;DR

This study investigates the complex magnetization behavior and thermomagnetic history effects in SmMn$_2$Ge$_2$, revealing unusual irreversibility patterns linked to metastable phase supercooling and superheating across a first order magnetic transition.

Contribution

It provides detailed insights into thermomagnetic irreversibility and metastable phase behavior in SmMn$_2$Ge$_2$, highlighting the influence of magnetic history on phase transitions.

Findings

Higher thermomagnetic irreversibility at 135 K in intermediate fields.

Supercooling and superheating affect phase stability and irreversibility.

Metastable phases contribute to magnetic hysteresis.

Abstract

The intermetallic compound SmMn$_2$Ge$_2$, displaying multiple magnetic phase transitions, is being investigated in detail for its magnetization behavior near the 145 K first order ferromagnetic to antiferromagnetic transition occuring on cooling, in particular for thermomagnetic history effects in the magnetization data. The most unusual finding is that the thermomagnetic irreversibility, [= M$^{FCW}$(T)-M$^{ZFC}$(T)] at 135 K is higher in intermediate magnetic field strengths. By studying the response of the sample (i.e., thermomagnetic irreversibility and thermal hysteresis) to different histories of application of magnetic field and temperature, we demonstrate how the supercooling and superheating of the metastable magnetic phases across the first order transition at 145 K contribute to overall thermomagnetic irreversibility.