Effect of transition element doping on crystal structure of rare earth borosilicides REB44Si2

On a previous study on samples of doped-YB44Si2, an improvement of thermoelectric properties has been achieved. Regarding the interesting effect of the doping of transition elements on the thermoelectric properties, a single crystal study has been carried out on Zn doped, Rh doped and Ni doped samples to assess how the transition element doping affects the crystal structure. Refinements were carried out based on the structural model solution of YB44Si2 reported in a previous study. Variations in the silicon contents were found in the doped single crystals. Splitting of partially occupied sites has also been detected for some of the doped samples. In this paper we present differences in the partial occupations of boron and silicon sites. Possibility of transition elements insertions based on the differences in crystal structures will be presented.

Graphical AbstractNew transition elements doped YB44Si2 were synthesized and have nominal compositions YB41.1Si1.1Rh0.02 and YB41Si1.3Ni0.06. Insertion of transition elements into the crystal structure of YB44Si2 leads to the transformation of B12 icosahedra into B11 polyhedrons for a few percent of them.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Differences in the partial occupations of boron and silicon sites→Possibility of transition elements insertions. ► Mixed occupancy of split positions. ► Insertion of transition elements between B12 icosahedra.