Magnetoelastic effects in Sm2IrIn8

In this work we report the results of high resolution temperature dependence X-ray diffraction measurements taken on single crystals of Sm$_{2}$IrIn$_{8}$ at the XRD2 beamline of Laboratorio Nacional de Luz Sincrotron (LNLS), in Campinas, Brazil. Our data reveal the existence of a magnetostrictive tetragonal-to-orthorhombic phase transition at 14.2 K coincidently to the first order antiferromagnetic transition. For T$<$T$_{N}$ the mismatch between the $a$ and $b$ lattice parameters increases continuously with decreasing temperature up to a value of $\raise0.7ex\hbox{$a$} \!\mathord{\left/ {\vphantom {a b}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$b$}-1\approx $ 0.44 {\%} at the lowest temperature measured, T = 10K.