Structural Distortion and Magnetic Order in the Intermetallic ${\hbox{Eu}}_{3}{\hbox{Ir}}_{4}{\hbox{Sn}}_{13}$ Compound

In this work, we have investigated the low temperature structural distortion and magnetic properties of the Eu 3 Ir 4 Sn 13 Remeika cubic phase compound using X-ray powder diffraction (XRD), X-ray resonant magnetic scattering (XRMS) and neutron diffraction. X-ray scattering revealed that the peak observed in electrical resistivity and heat capacity measurements is related to a structural distortion at T*=57.1 K. This crystallographic distortion characterized by the arising of a propagation vector q → =(0,(1/2),(1/2)) is due to a displacement of the Sn ions at the Sn1Sn2 12 polyhedron. In addition, the neutron diffraction experiments performed on a single crystal of Eu 3 Ir 4 Sn 13 exhibit an antiferromagnetic coupling below T N =10.1 K where we observe a commensurate magnetic propagation vector τ → =(0,(1/2),(1/2)) identical to the one observed for the structural distortion.