Er1.33Pt3Ga8: A modulated variant of the Er4Pt9Al24-structure type

• Single crystals of Er1.33Pt3Ga8 were grown from gallium flux.
• The structure of Er1.33Pt3Ga8 is compared to Er4Pt9Al24.
• Structure has been solved in the monoclinic superspace group X2/m(0β0)00 with a commensurate modulated vector q=1/3b*.

Single crystals of Er1.33Pt3Ga8 were synthesized in a molten Ga flux. Er1.33Pt3Ga8 can be considered to be a modulated variant of the Er4Pt9Al24-structure type, where the partial occupancies are ordered. Indeed, the presence of weak satellite reflections indicates a complex organization and distribution of the Er and Ga atoms within the [ErGa] slabs. The structure has been solved based on single crystal X-ray diffraction data in the monoclinic superspace group X2/m(0β0)00 with a commensurate modulated vector q=1/3b*. Precession images also indicate diffusion in the perpendicular direction indicating a partial disorder of this arrangement from layer to layer. In addition, Er1.33Pt3Ga8 shows antiferromagnetic ordering at TN~5 K.

A precession image of the hk0 zone showing weak, periodic, unindexed reflections indicating modulation and representation of the commensurate [ErGa] layer showing the waving modulated occupation.Figure optionsDownload as PowerPoint slide