Study of Eu3Ir4Sn13-xGax structural and magnetic properties

Abstract

In this work, Eu3Ir4Sn13-xGax single crystals with different Ga-concentration will be grown by self-flux technique and we will study how chemical substitution affects electrical, magnetic and structural properties of the compound. The intermetallic compounds R4M3Sn13 (R = Eu, La, Ce, Ca, etc; M = Rh, Ir, Co) are known to present several interesting properties such as antiferromagnetic ordering, superconductivity and heavy fermion behaviour. In particular, the Eu3Ir4Sn13 compound has an antiferromagnetic transition around TN ~ 11 K and a peculiar structural transition around T* ~ 60 K. This last transition is due to the displacement of Sn ions in the polyhedron formed by Sn inside the cubic lattice. This work aims to study how the structural transition is affected by Ga substitution in the Sn sites. Since Ga ions are smaller than Sn ions, this substitution should work as a chemical pressure. Also, once Ga has one p eletron absent in comparison to Sn, so it might introduce some electronic effects.Previous studies have shown that, under hidrostatic pressure, the structural transition is shifted to lower temperatures, while the antiferromagnetic is barely changed. Preliminary results show that Ga substitution has similar properties, strongly suppressing the structural transition and leaving TN almost unchanged. Therefore, this study ca shed some light on important information about the nature of these transitions. The single crystals properties will be studied through magnetic susceptibility, heat capacity and electrical resistivity measurements and, later, by microscopic techniques in future projects. (AU)